diff --git a/src/gtk/dialog.cpp b/src/gtk/dialog.cpp
index 2ff8564b78..75b82b7303 100644
--- a/src/gtk/dialog.cpp
+++ b/src/gtk/dialog.cpp
@@ -118,7 +118,7 @@ int wxDialog::ShowModal()
         wxWindow *parent = wxTheApp->GetTopWindow();
         if ( parent &&
                 parent != this &&
-                    parent->IsBeingDeleted() &&
+                    !parent->IsBeingDeleted() &&
                         !(parent->GetExtraStyle() & wxWS_EX_TRANSIENT) )
         {
             m_parent = parent;
diff --git a/src/gtk1/dialog.cpp b/src/gtk1/dialog.cpp
index 67f0984c08..5a1129b0e2 100644
--- a/src/gtk1/dialog.cpp
+++ b/src/gtk1/dialog.cpp
@@ -194,7 +194,7 @@ int wxDialog::ShowModal()
         wxWindow *parent = wxTheApp->GetTopWindow();
         if ( parent &&
                 parent != this &&
-                    parent->IsBeingDeleted() &&
+                    !parent->IsBeingDeleted() &&
                         !(parent->GetExtraStyle() & wxWS_EX_TRANSIENT) )
         {
             m_parent = parent;