diff --git a/dlls/comctl32/updown.c b/dlls/comctl32/updown.c
index a4b9271b270..149de29c69d 100644
--- a/dlls/comctl32/updown.c
+++ b/dlls/comctl32/updown.c
@@ -328,7 +328,7 @@ static BOOL UPDOWN_SetBuddyInt (const UPDOWN_INFO *infoPtr)
 
 
     /* Do thousands separation if necessary */
-    if (!(infoPtr->dwStyle & UDS_NOTHOUSANDS) && (len > 3)) {
+    if ((infoPtr->Base == 10) && !(infoPtr->dwStyle & UDS_NOTHOUSANDS) && (len > 3)) {
         WCHAR tmp[COUNT_OF(txt)], *src = tmp, *dst = txt;
         WCHAR sep = UPDOWN_GetThousandSep();
 	int start = len % 3;