diff --git a/mercurial/rcutil.py b/mercurial/rcutil.py
--- a/mercurial/rcutil.py
+++ b/mercurial/rcutil.py
@@ -29,7 +29,8 @@
     p = util.expandpath(path)
     if os.path.isdir(p):
         join = os.path.join
-        return [join(p, f) for f, k in util.listdir(p) if f.endswith('.rc')]
+        return sorted(join(p, f) for f, k in util.listdir(p)
+                      if f.endswith('.rc'))
     return [p]
 
 def envrcitems(env=None):
diff --git a/tests/test-config.t b/tests/test-config.t
--- a/tests/test-config.t
+++ b/tests/test-config.t
@@ -211,3 +211,12 @@
   $ hg log --template '{author}\n'
   repo user
   $ cd ..
+
+configs should be readon in lexicographical order
+
+  $ mkdir configs
+  $ for i in `$TESTDIR/seq.py 10 99`; do
+  >    printf "[section]\nkey=$i" > configs/$i.rc
+  > done
+  $ HGRCPATH=configs hg config section.key
+  99