diff --git a/hgext/churn.py b/hgext/churn.py
--- a/hgext/churn.py
+++ b/hgext/churn.py
@@ -161,7 +161,7 @@
     if not aliases and os.path.exists(repo.wjoin('.hgchurn')):
         aliases = repo.wjoin('.hgchurn')
     if aliases:
-        for l in open(aliases, "r"):
+        for l in open(aliases, "rb"):
             try:
                 alias, actual = l.rsplit('=' in l and '=' or None, 1)
                 amap[alias.strip()] = actual.strip()
diff --git a/mercurial/crecord.py b/mercurial/crecord.py
--- a/mercurial/crecord.py
+++ b/mercurial/crecord.py
@@ -554,7 +554,7 @@
     """
     chunkselector = curseschunkselector(headerlist, ui, operation)
     if testfn and os.path.exists(testfn):
-        testf = open(testfn)
+        testf = open(testfn, 'rb')
         testcommands = [x.rstrip('\n') for x in testf.readlines()]
         testf.close()
         while True: