diff --git a/reactos/base/applications/dxdiag/display.c b/reactos/base/applications/dxdiag/display.c
index 5cef4efb698..77b6fd337d7 100644
--- a/reactos/base/applications/dxdiag/display.c
+++ b/reactos/base/applications/dxdiag/display.c
@@ -213,7 +213,7 @@ InitializeDialog(HWND hwndDlg, PDISPLAY_DEVICEW pDispDevice)
     HKEY hKey;
     HWND hDlgCtrls[5];
     DWORD dwMemory;
-    DEVMODE DevMode;
+    DEVMODEW DevMode;
     IDirect3D9 * ppObj;
     D3DADAPTER_IDENTIFIER9 Identifier;
     HRESULT hResult;
@@ -276,7 +276,7 @@ InitializeDialog(HWND hwndDlg, PDISPLAY_DEVICEW pDispDevice)
     }
 
     /* retrieve current display mode */
-    DevMode.dmSize = sizeof(DEVMODE);
+    DevMode.dmSize = sizeof(DEVMODEW);
     if (EnumDisplaySettingsW(pDispDevice->DeviceName, ENUM_CURRENT_SETTINGS, &DevMode))
     {
         szFormat[0] = L'\0';
diff --git a/reactos/base/applications/dxdiag/dxdiag.c b/reactos/base/applications/dxdiag/dxdiag.c
index 2c9bc701baf..808f92b673a 100644
--- a/reactos/base/applications/dxdiag/dxdiag.c
+++ b/reactos/base/applications/dxdiag/dxdiag.c
@@ -50,7 +50,7 @@ InsertTabCtrlItem(HWND hDlgCtrl, INT Position, LPWSTR uId)
     TCITEMW item;
 
     /* setup item info */
-    memset(&item, 0, sizeof(TCITEM));
+    memset(&item, 0, sizeof(TCITEMW));
     item.mask = TCIF_TEXT;
 
     /* load item name */