diff --git a/ChangeLog b/ChangeLog
index f993421cba..7e576be898 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 Fri May  9 10:01:34 EST 2008 Jim Meyering <meyering@redhat.com>
 
+	avoid one more ctype vs. sign-extension problem
+	* src/util.c (TOLOWER): Also convert tolower argument.
+
 	add "const" and "static" attributes to file-scoped globals
 	* src/storage_backend_fs.c (fileTypeInfo): Add "static" and two
 	"const" attributes.
diff --git a/src/util.c b/src/util.c
index 8f3cef9aa9..4cef6d23c7 100644
--- a/src/util.c
+++ b/src/util.c
@@ -57,7 +57,8 @@
 
 #define MAX_ERROR_LEN   1024
 
-#define TOLOWER(Ch) (isupper (to_uchar(Ch)) ? tolower (Ch) : (Ch))
+#define TOLOWER(Ch) (isupper (to_uchar(Ch)) \
+		     ? tolower (to_uchar (Ch)) : (to_uchar (Ch)))
 
 #define virLog(msg...) fprintf(stderr, msg)