diff --git a/core/AmAudio.h b/core/AmAudio.h
index d26a74ff..328fe8ff 100644
--- a/core/AmAudio.h
+++ b/core/AmAudio.h
@@ -66,6 +66,7 @@ public:
   };
 
   AmAudioEvent(int id):AmEvent(id){}
+  virtual ~AmAudioEvent() { }
 };
 
 
diff --git a/core/AmB2ABSession.h b/core/AmB2ABSession.h
index 62c2bb3a..57a8a101 100644
--- a/core/AmB2ABSession.h
+++ b/core/AmB2ABSession.h
@@ -177,7 +177,7 @@ class AmB2ABSession: public AmSession
 
   AmB2ABSession();
   AmB2ABSession(const string& other_local_tag);
-  ~AmB2ABSession();
+  virtual ~AmB2ABSession();
 
   void onBye(const AmSipRequest& req);
 
diff --git a/core/AmStats.h b/core/AmStats.h
index 3627f753..f765c363 100644
--- a/core/AmStats.h
+++ b/core/AmStats.h
@@ -48,6 +48,8 @@ class MeanValue
     n_val(0)
     {}
 
+  virtual ~MeanValue() { }
+
   void push(double val){
     cum_val += val;
     n_val++;