diff --git a/dlls/d3dx9_36/d3dx9_36.spec b/dlls/d3dx9_36/d3dx9_36.spec
index 5c880a49234..4278ae1f239 100644
--- a/dlls/d3dx9_36/d3dx9_36.spec
+++ b/dlls/d3dx9_36/d3dx9_36.spec
@@ -8,7 +8,7 @@
 @ stdcall D3DXCheckTextureRequirements(ptr ptr ptr ptr long ptr ptr)
 @ stdcall D3DXCheckVersion(long long)
 @ stdcall D3DXCheckVolumeTextureRequirements(ptr ptr ptr ptr ptr long ptr ptr)
-@ stub D3DXCleanMesh(ptr ptr ptr ptr ptr)
+@ stdcall D3DXCleanMesh(long ptr ptr ptr ptr ptr)
 @ stdcall D3DXColorAdjustContrast(ptr ptr float)
 @ stdcall D3DXColorAdjustSaturation(ptr ptr float)
 @ stdcall D3DXCompileShader(ptr long ptr ptr str str long ptr ptr ptr)
diff --git a/dlls/d3dx9_36/mesh.c b/dlls/d3dx9_36/mesh.c
index 35365ebde9e..de4049afc44 100644
--- a/dlls/d3dx9_36/mesh.c
+++ b/dlls/d3dx9_36/mesh.c
@@ -3818,6 +3818,14 @@ cleanup:
     return hr;
 }
 
+HRESULT WINAPI D3DXCleanMesh(D3DXCLEANTYPE clean_type, LPD3DXMESH mesh_in, const DWORD *adjacency_in,
+                             LPD3DXMESH *mesh_out, DWORD *adjacency_out, LPD3DXBUFFER *errors_and_warnings)
+{
+    FIXME("(%u, %p, %p, %p, %p, %p)\n", clean_type, mesh_in, adjacency_in, mesh_out, adjacency_out, errors_and_warnings);
+
+    return E_NOTIMPL;
+}
+
 HRESULT WINAPI D3DXFrameDestroy(LPD3DXFRAME frame, LPD3DXALLOCATEHIERARCHY alloc_hier)
 {
     HRESULT hr;