diff --git a/src/Mod/Part/App/BSplineSurfacePyImp.cpp b/src/Mod/Part/App/BSplineSurfacePyImp.cpp
index 9b368f476f..6c0bc66281 100644
--- a/src/Mod/Part/App/BSplineSurfacePyImp.cpp
+++ b/src/Mod/Part/App/BSplineSurfacePyImp.cpp
@@ -447,10 +447,10 @@ PyObject* BSplineSurfacePy::setVKnot(PyObject *args)
     Handle(Geom_BSplineSurface) surf = Handle(Geom_BSplineSurface)::DownCast
         (getGeometryPtr()->handle());
     if (M == -1) {
-        surf->SetUKnot(Index, K);
+        surf->SetVKnot(Index, K);
     }
     else {
-        surf->SetUKnot(Index, K, M);
+        surf->SetVKnot(Index, K, M);
     }
 
     Py_Return;