diff --git a/cmdline/cmdline_parser_test.cc b/cmdline/cmdline_parser_test.cc
index 288f7ac..b740b41 100644
--- a/cmdline/cmdline_parser_test.cc
+++ b/cmdline/cmdline_parser_test.cc
@@ -202,6 +202,7 @@
   EXPECT_SINGLE_PARSE_VALUE(false, "-XX:DisableHSpaceCompactForOOM", M::EnableHSpaceCompactForOOM);
   EXPECT_SINGLE_PARSE_VALUE(0.5, "-XX:HeapTargetUtilization=0.5", M::HeapTargetUtilization);
   EXPECT_SINGLE_PARSE_VALUE(5u, "-XX:ParallelGCThreads=5", M::ParallelGCThreads);
+  EXPECT_SINGLE_PARSE_EXISTS("-Xno-dex-file-fallback", M::NoDexFileFallback);
 }  // TEST_F
 
 TEST_F(CmdlineParserTest, TestSimpleFailures) {
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index ee66b49..3278751 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -1008,10 +1008,15 @@
 
   // Failed, bail.
   if (open_oat_file.get() == nullptr) {
-    std::string error_msg;
     // dex2oat was disabled or crashed. Add the dex file in the list of dex_files to make progress.
-    DexFile::Open(dex_location, dex_location, &error_msg, dex_files);
-    error_msgs->push_back(error_msg);
+    if (Runtime::Current()->IsDexFileFallbackEnabled()) {
+      std::string error_msg;
+      if (!DexFile::Open(dex_location, dex_location, &error_msg, dex_files)) {
+        error_msgs->push_back(error_msg);
+      }
+    } else {
+      error_msgs->push_back("Fallback mode disabled, skipping dex files.");
+    }
     return false;
   }
 
diff --git a/runtime/parsed_options.cc b/runtime/parsed_options.cc
index 99369ca..c0c7baa 100644
--- a/runtime/parsed_options.cc
+++ b/runtime/parsed_options.cc
@@ -241,6 +241,8 @@
       .Define("-Xzygote-max-failed-boots=_")
           .WithType<unsigned int>()
           .IntoKey(M::ZygoteMaxFailedBoots)
+      .Define("-Xno-dex-file-fallback")
+          .IntoKey(M::NoDexFileFallback)
       .Ignore({
           "-ea", "-da", "-enableassertions", "-disableassertions", "--runtime-arg", "-esa",
           "-dsa", "-enablesystemassertions", "-disablesystemassertions", "-Xrs", "-Xint:_",
@@ -631,6 +633,8 @@
   UsageMessage(stream, "  -X[no]relocate\n");
   UsageMessage(stream, "  -X[no]dex2oat (Whether to invoke dex2oat on the application)\n");
   UsageMessage(stream, "  -X[no]image-dex2oat (Whether to create and use a boot image)\n");
+  UsageMessage(stream, "  -Xno-dex-file-fallback "
+                       "(Don't fall back to dex files without oat files)\n");
   UsageMessage(stream, "\n");
 
   UsageMessage(stream, "The following previously supported Dalvik options are ignored:\n");
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index f38f65e..1af08c1 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -169,6 +169,7 @@
       dump_gc_performance_on_shutdown_(false),
       preinitialization_transaction_(nullptr),
       verify_(false),
+      allow_dex_file_fallback_(true),
       target_sdk_version_(0),
       implicit_null_checks_(false),
       implicit_so_checks_(false),
@@ -380,7 +381,9 @@
   InitLogging(NULL);  // Calls Locks::Init() as a side effect.
   instance_ = new Runtime;
   if (!instance_->Init(options, ignore_unrecognized)) {
-    delete instance_;
+    // TODO: Currently deleting the instance will abort the runtime on destruction. Now This will
+    // leak memory, instead. Fix the destructor. b/19100793.
+    // delete instance_;
     instance_ = NULL;
     return false;
   }
@@ -762,6 +765,7 @@
   intern_table_ = new InternTable;
 
   verify_ = runtime_options.GetOrDefault(Opt::Verify);
+  allow_dex_file_fallback_ = !runtime_options.Exists(Opt::NoDexFileFallback);
 
   if (runtime_options.GetOrDefault(Opt::Interpret)) {
     GetInstrumentation()->ForceInterpretOnly();
@@ -800,6 +804,11 @@
                        runtime_options.GetOrDefault(Opt::EnableHSpaceCompactForOOM),
                        runtime_options.GetOrDefault(Opt::HSpaceCompactForOOMMinIntervalsMs));
 
+  if (heap_->GetImageSpace() == nullptr && !allow_dex_file_fallback_) {
+    LOG(ERROR) << "Dex file fallback disabled, cannot continue without image.";
+    return false;
+  }
+
   dump_gc_performance_on_shutdown_ = runtime_options.Exists(Opt::DumpGCPerformanceOnShutdown);
 
   if (runtime_options.Exists(Opt::JdwpOptions)) {
diff --git a/runtime/runtime.h b/runtime/runtime.h
index fb9ca40..944c8bd 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -505,6 +505,10 @@
     return verify_;
   }
 
+  bool IsDexFileFallbackEnabled() const {
+    return allow_dex_file_fallback_;
+  }
+
   bool RunningOnValgrind() const {
     return running_on_valgrind_;
   }
@@ -668,6 +672,10 @@
   // If false, verification is disabled. True by default.
   bool verify_;
 
+  // If true, the runtime may use dex files directly with the interpreter if an oat file is not
+  // available/usable.
+  bool allow_dex_file_fallback_;
+
   // Specifies target SDK version to allow workarounds for certain API levels.
   int32_t target_sdk_version_;
 
diff --git a/runtime/runtime_options.def b/runtime/runtime_options.def
index 71a0152..d9cc4d4 100644
--- a/runtime/runtime_options.def
+++ b/runtime/runtime_options.def
@@ -115,6 +115,6 @@
                                                                           // Runtime::Abort.
 RUNTIME_OPTIONS_KEY (void (*)(),          HookAbort,                      nullptr)
 RUNTIME_OPTIONS_KEY (unsigned int,        ZygoteMaxFailedBoots,           1)
-
+RUNTIME_OPTIONS_KEY (Unit,                NoDexFileFallback)
 
 #undef RUNTIME_OPTIONS_KEY
diff --git a/test/116-nodex2oat/run b/test/116-nodex2oat/run
index 9e5c7dd..2cdb3f7 100755
--- a/test/116-nodex2oat/run
+++ b/test/116-nodex2oat/run
@@ -24,7 +24,7 @@
   exit 1
 fi
 
-# Make sure we can run without an oat file,
+# Make sure we can run without an oat file.
 echo "Run -Xnodex2oat"
 ${RUN} ${flags} --runtime-option -Xnodex2oat
 
diff --git a/test/118-noimage-dex2oat/expected.txt b/test/118-noimage-dex2oat/expected.txt
index bcb695d..0103e89 100644
--- a/test/118-noimage-dex2oat/expected.txt
+++ b/test/118-noimage-dex2oat/expected.txt
@@ -1,6 +1,8 @@
 Run -Xnoimage-dex2oat
 Has image is false, is image dex2oat enabled is false, is BOOTCLASSPATH on disk is false.
 testB18485243 PASS
+Run -Xnoimage-dex2oat -Xno-dex-file-fallback
+Failed to initialize runtime (check log for details)
 Run -Ximage-dex2oat
 Has image is true, is image dex2oat enabled is true, is BOOTCLASSPATH on disk is true.
 testB18485243 PASS
diff --git a/test/118-noimage-dex2oat/run b/test/118-noimage-dex2oat/run
index 2037797..4b1d0ce 100644
--- a/test/118-noimage-dex2oat/run
+++ b/test/118-noimage-dex2oat/run
@@ -46,10 +46,14 @@
 bpath_arg="--runtime-option -Xbootclasspath:${bpath}"
 
 
-# Make sure we can run without an oat file,
+# Make sure we can run without an oat file.
 echo "Run -Xnoimage-dex2oat"
 ${RUN} ${flags} ${bpath_arg} --runtime-option -Xnoimage-dex2oat --runtime-option -Xnodex2oat
 
+# Make sure we cannot run without an oat file without fallback.
+echo "Run -Xnoimage-dex2oat -Xno-dex-file-fallback"
+${RUN} ${flags} ${bpath_arg} --runtime-option -Xnoimage-dex2oat --runtime-option -Xnodex2oat --runtime-option -Xno-dex-file-fallback
+
 # Make sure we can run with the oat file.
 echo "Run -Ximage-dex2oat"
 ${RUN} ${flags} ${bpath_arg} --runtime-option -Ximage-dex2oat
diff --git a/test/119-noimage-patchoat/check b/test/119-noimage-patchoat/check
new file mode 100755
index 0000000..7b47ac1
--- /dev/null
+++ b/test/119-noimage-patchoat/check
@@ -0,0 +1,20 @@
+#!/bin/bash
+#
+# Copyright (C) 2014 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Strip the process pids and line numbers from exact error messages.
+sed -e 's/^art E.*\] //' "$2" > "$2.tmp"
+
+diff --strip-trailing-cr -q "$1" "$2.tmp" >/dev/null
diff --git a/test/119-noimage-patchoat/expected.txt b/test/119-noimage-patchoat/expected.txt
index e864268..3d2b4f1 100644
--- a/test/119-noimage-patchoat/expected.txt
+++ b/test/119-noimage-patchoat/expected.txt
@@ -1,5 +1,8 @@
 Run -Xnoimage-dex2oat -Xpatchoat:/system/bin/false
 Has image is false, is image dex2oat enabled is false.
+Run -Xnoimage-dex2oat -Xpatchoat:/system/bin/false -Xno-dex-file-fallback
+Dex file fallback disabled, cannot continue without image.
+Failed to initialize runtime (check log for details)
 Run -Ximage-dex2oat
 Has image is true, is image dex2oat enabled is true.
 Run default
diff --git a/test/119-noimage-patchoat/run b/test/119-noimage-patchoat/run
index c409cbb..02a64f8 100644
--- a/test/119-noimage-patchoat/run
+++ b/test/119-noimage-patchoat/run
@@ -29,10 +29,14 @@
   false_bin="/system/bin/false"
 fi
 
-# Make sure we can run without an image file,
+# Make sure we can run without an image file.
 echo "Run -Xnoimage-dex2oat -Xpatchoat:/system/bin/false"
 ${RUN} ${flags} ${BPATH} --runtime-option -Xnoimage-dex2oat --runtime-option -Xpatchoat:${false_bin}
 
+# Make sure we cannot run without an image file without fallback.
+echo "Run -Xnoimage-dex2oat -Xpatchoat:/system/bin/false -Xno-dex-file-fallback"
+${RUN} ${flags} ${BPATH} --runtime-option -Xnoimage-dex2oat --runtime-option -Xpatchoat:${false_bin} --runtime-option -Xno-dex-file-fallback
+
 # Make sure we can run with the image file.
 echo "Run -Ximage-dex2oat"
 ${RUN} ${flags} ${BPATH} --runtime-option -Ximage-dex2oat
diff --git a/test/134-nodex2oat-nofallback/check b/test/134-nodex2oat-nofallback/check
new file mode 100755
index 0000000..d929c8f
--- /dev/null
+++ b/test/134-nodex2oat-nofallback/check
@@ -0,0 +1,32 @@
+#!/bin/bash
+#
+# Copyright (C) 2014 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# The head of the log.
+HEAD=$(head -n 1 "$2")
+EXPECTED_HEAD="Unable to locate class 'Main'"
+
+# Content somewhere inside the output.
+grep 'Suppressed: java.io.IOException: Fallback mode disabled, skipping dex files.' "$2" >/dev/null
+MSG_FOUND=$?
+
+if [[ "$HEAD" != "$EXPECTED_HEAD" || $MSG_FOUND -ne 0 ]] ; then
+  # Print out the log and return with error.
+  cat "$2"
+  exit 1
+fi
+
+# Success.
+exit 0
\ No newline at end of file
diff --git a/test/134-nodex2oat-nofallback/expected.txt b/test/134-nodex2oat-nofallback/expected.txt
new file mode 100644
index 0000000..9b6c846
--- /dev/null
+++ b/test/134-nodex2oat-nofallback/expected.txt
@@ -0,0 +1,64 @@
+# This file isn't used, but gives an example of the output we expect.
+Unable to locate class 'Main'
+java.lang.ClassNotFoundException: Didn't find class "Main" on path: DexPathList[[zip file "/tmp/user/test-12345/134-nodex2oat-nofallback.jar"],nativeLibraryDirectories=[/ssd2/aosp-master3/out/host/linux-x86/lib]]
+       at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
+       at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
+       at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
+       Suppressed: java.io.IOException: Fallback mode disabled, skipping dex files.
+               at dalvik.system.DexFile.openDexFileNative(Native Method)
+               at dalvik.system.DexFile.openDexFile(DexFile.java:295)
+               at dalvik.system.DexFile.<init>(DexFile.java:80)
+               at dalvik.system.DexFile.<init>(DexFile.java:59)
+               at dalvik.system.DexPathList.loadDexFile(DexPathList.java:262)
+               at dalvik.system.DexPathList.makeDexElements(DexPathList.java:231)
+               at dalvik.system.DexPathList.<init>(DexPathList.java:109)
+               at dalvik.system.BaseDexClassLoader.<init>(BaseDexClassLoader.java:48)
+               at dalvik.system.PathClassLoader.<init>(PathClassLoader.java:38)
+               at java.lang.ClassLoader.createSystemClassLoader(ClassLoader.java:128)
+               at java.lang.ClassLoader.access$000(ClassLoader.java:65)
+               at java.lang.ClassLoader$SystemClassLoader.<clinit>(ClassLoader.java:81)
+               at java.lang.ClassLoader.getSystemClassLoader(ClassLoader.java:137)
+       Caused by: java.io.IOException: Failed to open oat file from dex location '/tmp/user/test-12345/134-nodex2oat-nofallback.jar'
+               ... 13 more
+       Caused by: java.io.IOException: Failed to open oat file from /tmp/user/test-12345/x86/134-nodex2oat-nofallback.odex (error Failed to open oat filename for reading: No such file or directory) (no dalvik_cache availible) and relocation failed.
+               ... 13 more
+       Caused by: java.io.IOException 
+               ... 13 more
+       Suppressed: java.lang.ClassNotFoundException: Main
+               at java.lang.Class.classForName(Native Method)
+               at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
+               at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
+               at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
+               ... 1 more
+       Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available
+java.lang.ClassNotFoundException: Didn't find class "Main" on path: DexPathList[[zip file "/tmp/user/test-12345/134-nodex2oat-nofallback.jar"],nativeLibraryDirectories=[/ssd2/aosp-master3/out/host/linux-x86/lib]]
+       at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
+       at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
+       at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
+       Suppressed: java.io.IOException: Fallback mode disabled, skipping dex files.
+               at dalvik.system.DexFile.openDexFileNative(Native Method)
+               at dalvik.system.DexFile.openDexFile(DexFile.java:295)
+               at dalvik.system.DexFile.<init>(DexFile.java:80)
+               at dalvik.system.DexFile.<init>(DexFile.java:59)
+               at dalvik.system.DexPathList.loadDexFile(DexPathList.java:262)
+               at dalvik.system.DexPathList.makeDexElements(DexPathList.java:231)
+               at dalvik.system.DexPathList.<init>(DexPathList.java:109)
+               at dalvik.system.BaseDexClassLoader.<init>(BaseDexClassLoader.java:48)
+               at dalvik.system.PathClassLoader.<init>(PathClassLoader.java:38)
+               at java.lang.ClassLoader.createSystemClassLoader(ClassLoader.java:128)
+               at java.lang.ClassLoader.access$000(ClassLoader.java:65)
+               at java.lang.ClassLoader$SystemClassLoader.<clinit>(ClassLoader.java:81)
+               at java.lang.ClassLoader.getSystemClassLoader(ClassLoader.java:137)
+       Caused by: java.io.IOException: Failed to open oat file from dex location '/tmp/user/test-12345/134-nodex2oat-nofallback.jar'
+               ... 13 more
+       Caused by: java.io.IOException: Failed to open oat file from /tmp/user/test-12345/x86/134-nodex2oat-nofallback.odex (error Failed to open oat filename for reading: No such file or directory) (no dalvik_cache availible) and relocation failed.
+               ... 13 more
+       Caused by: java.io.IOException: 
+               ... 13 more
+       Suppressed: java.lang.ClassNotFoundException: Main
+               at java.lang.Class.classForName(Native Method)
+               at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
+               at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
+               at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
+               ... 1 more
+       Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available
diff --git a/test/134-nodex2oat-nofallback/info.txt b/test/134-nodex2oat-nofallback/info.txt
new file mode 100644
index 0000000..3004729
--- /dev/null
+++ b/test/134-nodex2oat-nofallback/info.txt
@@ -0,0 +1,2 @@
+Test that disables dex2oat'ing the application, and disable fallback. This is derived from test
+116. It needs it separate test as it needs a custom check script.
\ No newline at end of file
diff --git a/test/134-nodex2oat-nofallback/run b/test/134-nodex2oat-nofallback/run
new file mode 100755
index 0000000..38b4adb
--- /dev/null
+++ b/test/134-nodex2oat-nofallback/run
@@ -0,0 +1,20 @@
+#!/bin/bash
+#
+# Copyright (C) 2014 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+flags="${@}"
+
+# Make sure we cannot run without an oat file without fallback.
+${RUN} ${flags} --runtime-option -Xnodex2oat --runtime-option -Xno-dex-file-fallback
diff --git a/test/134-nodex2oat-nofallback/src/Main.java b/test/134-nodex2oat-nofallback/src/Main.java
new file mode 100644
index 0000000..37ac9d5
--- /dev/null
+++ b/test/134-nodex2oat-nofallback/src/Main.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+public class Main {
+  public static void main(String[] args) {
+    System.out.println(
+        "Has oat is " + hasOat() + ", is dex2oat enabled is " + isDex2OatEnabled() + ".");
+
+    if (hasOat() && !isDex2OatEnabled()) {
+      throw new Error("Application with dex2oat disabled runs with an oat file");
+    } else if (!hasOat() && isDex2OatEnabled()) {
+      throw new Error("Application with dex2oat enabled runs without an oat file");
+    }
+  }
+
+  static {
+    System.loadLibrary("arttest");
+  }
+
+  private native static boolean hasOat();
+
+  private native static boolean isDex2OatEnabled();
+}
diff --git a/test/Android.run-test.mk b/test/Android.run-test.mk
index c8e0ec5..8e4b46b 100644
--- a/test/Android.run-test.mk
+++ b/test/Android.run-test.mk
@@ -181,7 +181,8 @@
 # Note 116-nodex2oat is not broken per-se it just doesn't (and isn't meant to) work with --prebuild.
 TEST_ART_BROKEN_PREBUILD_RUN_TESTS := \
   116-nodex2oat \
-  118-noimage-dex2oat
+  118-noimage-dex2oat \
+  134-nodex2oat-nofallback
 
 ifneq (,$(filter prebuild,$(PREBUILD_TYPES)))
   ART_TEST_KNOWN_BROKEN += $(call all-run-test-names,$(TARGET_TYPES),$(RUN_TYPES),prebuild, \