diff --git a/include/wx/dcgraph.h b/include/wx/dcgraph.h
index 18a173c435..c0fa7451b1 100644
--- a/include/wx/dcgraph.h
+++ b/include/wx/dcgraph.h
@@ -206,7 +206,6 @@ public:
 protected:
     // scaling variables
     bool m_logicalFunctionSupported;
-    double       m_mm_to_pix_x, m_mm_to_pix_y;
     wxGraphicsMatrix m_matrixOriginal;
     wxGraphicsMatrix m_matrixCurrent;