diff --git a/include/box2d/box2d.h b/include/box2d/box2d.h
index 328129250..240df1833 100644
--- a/include/box2d/box2d.h
+++ b/include/box2d/box2d.h
@@ -346,13 +346,6 @@ B2_API b2MassData b2Body_GetMassData( b2BodyId bodyId );
 /// You should call this regardless of body type.
 B2_API void b2Body_ApplyMassFromShapes( b2BodyId bodyId );
 
-/// Set the automatic mass setting. Normally this is set in b2BodyDef before creation.
-/// @see b2BodyDef::automaticMass
-B2_API void b2Body_SetAutomaticMass( b2BodyId bodyId, bool automaticMass );
-
-/// Get the automatic mass setting
-B2_API bool b2Body_GetAutomaticMass( b2BodyId bodyId );
-
 /// Adjust the linear damping. Normally this is set in b2BodyDef before creation.
 B2_API void b2Body_SetLinearDamping( b2BodyId bodyId, float linearDamping );
 
diff --git a/src/body.c b/src/body.c
index 7dc6f469b..d1d71501f 100644
--- a/src/body.c
+++ b/src/body.c
@@ -1260,25 +1260,6 @@ void b2Body_ApplyMassFromShapes( b2BodyId bodyId )
 	b2UpdateBodyMassData( world, body );
 }
 
-void b2Body_SetAutomaticMass( b2BodyId bodyId, bool automaticMass )
-{
-	b2World* world = b2GetWorldLocked( bodyId.world0 );
-	if ( world == NULL )
-	{
-		return;
-	}
-
-	b2Body* body = b2GetBodyFullId( world, bodyId );
-	body->automaticMass = automaticMass;
-}
-
-bool b2Body_GetAutomaticMass( b2BodyId bodyId )
-{
-	b2World* world = b2GetWorld( bodyId.world0 );
-	b2Body* body = b2GetBodyFullId( world, bodyId );
-	return body->automaticMass;
-}
-
 void b2Body_SetLinearDamping( b2BodyId bodyId, float linearDamping )
 {
 	B2_ASSERT( b2IsValid( linearDamping ) && linearDamping >= 0.0f );
diff --git a/src/body.h b/src/body.h
index 2265ed0b5..b36e410ae 100644
--- a/src/body.h
+++ b/src/body.h
@@ -67,7 +67,6 @@ typedef struct b2Body
 	bool fixedRotation;
 	bool isSpeedCapped;
 	bool isMarked;
-	bool automaticMass;
 } b2Body;
 
 // The body state is designed for fast conversion to and from SIMD via scatter-gather.