diff --git a/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp b/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp
index a196d4522..373357fe5 100644
--- a/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp
+++ b/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp
@@ -1533,6 +1533,8 @@ void	btDiscreteDynamicsWorld::serialize(btSerializer* serializer)
 
 	serializeRigidBodies(serializer);
 
+	serializeContactManifolds(serializer);
+
 	serializer->finishSerialization();
 }
 
diff --git a/src/BulletSoftBody/btSoftMultiBodyDynamicsWorld.cpp b/src/BulletSoftBody/btSoftMultiBodyDynamicsWorld.cpp
index 4e76dca9d..402102ea2 100644
--- a/src/BulletSoftBody/btSoftMultiBodyDynamicsWorld.cpp
+++ b/src/BulletSoftBody/btSoftMultiBodyDynamicsWorld.cpp
@@ -361,6 +361,8 @@ void	btSoftMultiBodyDynamicsWorld::serialize(btSerializer* serializer)
 
 	serializeCollisionObjects(serializer);
 
+	serializeContactManifolds(serializer);
+
 	serializer->finishSerialization();
 }