diff --git a/src/wifi/model/dcf-manager.cc b/src/wifi/model/dcf-manager.cc
index 821f091eb..8fa57a699 100644
--- a/src/wifi/model/dcf-manager.cc
+++ b/src/wifi/model/dcf-manager.cc
@@ -141,10 +141,7 @@ void
 DcfManager::SetupPhyListener (Ptr<WifiPhy> phy)
 {
   NS_LOG_FUNCTION (this << phy);
-  if (m_phyListener != 0)
-    {
-      delete m_phyListener;
-    }
+  NS_ASSERT (m_phyListener == 0);
   m_phyListener = new PhyListener (this);
   phy->RegisterListener (m_phyListener);
 }