diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index 0828578f0..9f7255b7f 100755
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -745,7 +745,7 @@ namespace detail
 			int conn = m_connections.size();
 #endif
 			(*m_connections.begin())->disconnect();
-			TORRENT_ASSERT(conn == m_connections.size() + 1);
+			TORRENT_ASSERT(conn == int(m_connections.size()) + 1);
 		}
 
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)