diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index 746d8e1808..48cca5b829 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -499,6 +499,8 @@ DEFINE_int(sim_stack_alignment, 8,
            "Stack alingment in bytes in simulator (4 or 8, 8 is default)")
 
 // isolate.cc
+DEFINE_bool(abort_on_uncaught_exception, false,
+            "abort program (dump core) when an uncaught exception is thrown")
 DEFINE_bool(trace_exception, false,
             "print stack trace when throwing exceptions")
 DEFINE_bool(preallocate_message_memory, false,
diff --git a/src/isolate.cc b/src/isolate.cc
index fd70002cce..e61c387b8d 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1213,6 +1213,7 @@ bool Isolate::IsErrorObject(Handle<Object> obj) {
   return false;
 }
 
+static int fatal_exception_depth = 0;
 
 void Isolate::DoThrow(Object* exception, MessageLocation* location) {
   ASSERT(!has_pending_exception());
@@ -1296,6 +1297,20 @@ void Isolate::DoThrow(Object* exception, MessageLocation* location) {
         thread_local_top()->pending_message_start_pos_ = location->start_pos();
         thread_local_top()->pending_message_end_pos_ = location->end_pos();
       }
+
+      // If the abort-on-uncaught-exception flag is specified, abort on any
+      // exception not caught by JavaScript, even when an external handler is
+      // present.  This flag is intended for use by JavaScript developers, so
+      // print a user-friendly stack trace (not an internal one).
+      if (fatal_exception_depth == 0 &&
+          FLAG_abort_on_uncaught_exception &&
+          (report_exception || can_be_caught_externally)) {
+        fatal_exception_depth++;
+        fprintf(stderr, "%s\n\nFROM\n",
+          *MessageHandler::GetLocalizedMessage(this, message_obj));
+        PrintCurrentStackTrace(stderr);
+        OS::Abort();
+      }
     } else if (location != NULL && !location->script().is_null()) {
       // We are bootstrapping and caught an error where the location is set
       // and we have a script for the location.