diff --git a/include/MySQL_Thread.h b/include/MySQL_Thread.h
index d09396f57..89783ef7b 100644
--- a/include/MySQL_Thread.h
+++ b/include/MySQL_Thread.h
@@ -71,7 +71,9 @@ class ProxySQL_Poll {
   ~ProxySQL_Poll() {
     unsigned int i;
     for (i=0;i<len;i++) {
-      if (myds[i]->myds_type==MYDS_LISTENER) {
+      if (
+				myds[i] && // fix bug #278 . This should be caused by not initialized datastreams used to ping the backend
+				myds[i]->myds_type==MYDS_LISTENER) {
         delete myds[i];
       }
     }
diff --git a/lib/MySQL_Thread.cpp b/lib/MySQL_Thread.cpp
index 99bd696fb..cbc0b7bb6 100644
--- a/lib/MySQL_Thread.cpp
+++ b/lib/MySQL_Thread.cpp
@@ -600,7 +600,9 @@ MySQL_Thread::~MySQL_Thread() {
 	}
 	unsigned int i;
 	for (i=0;i<mypolls.len;i++) {
-		if (mypolls.myds[i]->myds_type==MYDS_LISTENER) {
+		if (
+			mypolls.myds[i] && // fix bug #278 . This should be caused by not initialized datastreams used to ping the backend
+			mypolls.myds[i]->myds_type==MYDS_LISTENER) {
 			delete mypolls.myds[i];
 		}
 	}