diff -r 097a8580d33c st.c
--- a/st.c	Thu Oct 04 22:59:45 2012 +0200
+++ b/st.c	Fri Oct 05 14:39:03 2012 +0700
@@ -2234,7 +2234,7 @@
 			winy + font->ascent, (FcChar8 *)s, bytelen);
 
 	if(base.mode & ATTR_UNDERLINE) {
-		XftDrawRect(xw.xft_draw, fg, winx, winy+1,
+		XftDrawRect(xw.xft_draw, fg, winx, winy + font->ascent + 1,
 				width, 1);
 	}
 }