diff --git a/gtsam/slam/ProjectionFactor.h b/gtsam/slam/ProjectionFactor.h
index 77577fbb5..284d10a8c 100644
--- a/gtsam/slam/ProjectionFactor.h
+++ b/gtsam/slam/ProjectionFactor.h
@@ -67,6 +67,9 @@ namespace gtsam {
 				  Base(model, poseKey, pointKey), measured_(measured), K_(K) {
 		}
 
+		/** Virtual destructor */
+		virtual ~GenericProjectionFactor() {}
+
 		/**
 		 * print
 		 * @param s optional string naming the factor
diff --git a/gtsam/slam/StereoFactor.h b/gtsam/slam/StereoFactor.h
index 1eefacc96..ae2deeae3 100644
--- a/gtsam/slam/StereoFactor.h
+++ b/gtsam/slam/StereoFactor.h
@@ -54,7 +54,7 @@ public:
 		Base(model, poseKey, landmarkKey), measured_(measured), K_(K) {
 	}
 
-	~GenericStereoFactor() {}  ///< destructor
+	virtual ~GenericStereoFactor() {}  ///< Virtual destructor
 
 	/**
 	 * print