diff --git a/src/com/android/phone/CallModeler.java b/src/com/android/phone/CallModeler.java
index 13005ee..517a5a9 100644
--- a/src/com/android/phone/CallModeler.java
+++ b/src/com/android/phone/CallModeler.java
@@ -104,7 +104,9 @@
     public void addListener(Listener listener) {
         Preconditions.checkNotNull(listener);
         Preconditions.checkNotNull(mListeners);
-        mListeners.add(listener);
+        if (!mListeners.contains(listener)) {
+            mListeners.add(listener);
+        }
     }
 
     public List<Call> getFullList() {