diff --git a/src/org/jgroups/stack/RouterStubManager.java b/src/org/jgroups/stack/RouterStubManager.java
index e1d782573c..b629e68598 100644
--- a/src/org/jgroups/stack/RouterStubManager.java
+++ b/src/org/jgroups/stack/RouterStubManager.java
@@ -216,7 +216,10 @@ protected boolean add(Target target) {
 
     protected boolean remove(RouterStub stub) {
         if(stub == null) return false;
-        boolean retval=this.stubs.remove(stub);
+        boolean retval=false;
+        synchronized(stubs) {
+            retval=this.stubs.remove(stub);
+        }
         stub.destroy();
         return retval;
     }