diff --git a/dlls/user32/text.c b/dlls/user32/text.c
index da3444de5fe..b28bd711bb7 100644
--- a/dlls/user32/text.c
+++ b/dlls/user32/text.c
@@ -1081,6 +1081,7 @@ INT WINAPI DrawTextW( HDC hdc, LPCWSTR str, INT count, LPRECT rect, UINT flags )
     DRAWTEXTPARAMS dtp;
 
     memset (&dtp, 0, sizeof(dtp));
+    dtp.cbSize = sizeof(dtp);
     if (flags & DT_TABSTOP)
     {
         dtp.iTabLength = (flags >> 8) & 0xff;
@@ -1097,6 +1098,7 @@ INT WINAPI DrawTextA( HDC hdc, LPCSTR str, INT count, LPRECT rect, UINT flags )
     DRAWTEXTPARAMS dtp;
 
     memset (&dtp, 0, sizeof(dtp));
+    dtp.cbSize = sizeof(dtp);
     if (flags & DT_TABSTOP)
     {
         dtp.iTabLength = (flags >> 8) & 0xff;