diff --git a/ril/libsecril-client/secril-client.cpp b/ril/libsecril-client/secril-client.cpp
index d96f19b..a0bf078 100755
--- a/ril/libsecril-client/secril-client.cpp
+++ b/ril/libsecril-client/secril-client.cpp
@@ -1088,6 +1088,8 @@
     RilClientPrv *client_prv;
     int maxfd = -1;
 
+    unsigned int check_req_id = req_id;
+
     client_prv = (RilClientPrv *)(client->prv);
 
     // Allocate a token.
@@ -1126,6 +1128,13 @@
         goto error;
     }
 
+    // check if the handler for specified event is NULL and deregister token
+    // to prevent token pool overflow
+    if(!FindReqHandler(client_prv, token, &check_req_id)) {
+        FreeToken(&(client_prv->token_pool), token);
+        ClearReqHistory(client_prv, token);
+    }
+
     return RIL_CLIENT_ERR_SUCCESS;
 
 error: