diff --git a/include/wx/gtk/mdi.h b/include/wx/gtk/mdi.h
index f5fea52d5a..ec57a59548 100644
--- a/include/wx/gtk/mdi.h
+++ b/include/wx/gtk/mdi.h
@@ -23,6 +23,8 @@
 #include "wx/frame.h"
 #include "wx/toolbar.h"
 
+#if wxUSE_MDI_ARCHITECTURE
+
 //-----------------------------------------------------------------------------
 // classes
 //-----------------------------------------------------------------------------
@@ -212,5 +214,7 @@ private:
     DECLARE_DYNAMIC_CLASS(wxMDIClientWindow)
 };
 
+#endif // if USE_MDI...
+
 #endif // __MDIH__
 
diff --git a/include/wx/gtk1/mdi.h b/include/wx/gtk1/mdi.h
index f5fea52d5a..ec57a59548 100644
--- a/include/wx/gtk1/mdi.h
+++ b/include/wx/gtk1/mdi.h
@@ -23,6 +23,8 @@
 #include "wx/frame.h"
 #include "wx/toolbar.h"
 
+#if wxUSE_MDI_ARCHITECTURE
+
 //-----------------------------------------------------------------------------
 // classes
 //-----------------------------------------------------------------------------
@@ -212,5 +214,7 @@ private:
     DECLARE_DYNAMIC_CLASS(wxMDIClientWindow)
 };
 
+#endif // if USE_MDI...
+
 #endif // __MDIH__