diff --git a/hgext/churn.py b/hgext/churn.py
--- a/hgext/churn.py
+++ b/hgext/churn.py
@@ -129,10 +129,14 @@ def churn(ui, repo, *pats, **opts):
         aliases = repo.wjoin('.hgchurn')
     if aliases:
         for l in open(aliases, "r"):
-            if not l.strip():
+            try:
+                alias, actual = l.split('=' in l and '=' or None, 1)
+                amap[alias.strip()] = actual.strip()
+            except ValueError:
+                l = l.strip()
+                if l:
+                    ui.warn(_("skipping malformed alias: %s\n" % l))
                 continue
-            alias, actual = l.split('=' in l and '=' or None, 1)
-            amap[alias.strip()] = actual.strip()
 
     rate = countrate(ui, repo, amap, *pats, **opts).items()
     if not rate:
diff --git a/tests/test-churn b/tests/test-churn
--- a/tests/test-churn
+++ b/tests/test-churn
@@ -40,6 +40,7 @@ cat > ../aliases <<EOF
 user1 alias1
 
 user3 alias3
+not-an-alias
 EOF
 hg churn --aliases ../aliases
 echo % churn with .hgchurn
diff --git a/tests/test-churn.out b/tests/test-churn.out
--- a/tests/test-churn.out
+++ b/tests/test-churn.out
@@ -16,10 +16,12 @@ user1      2 ***************************
 user2      2 ***************************************************************
 user1      1 ********************************
 % churn with aliases
+skipping malformed alias: not-an-alias
 alias3      3 **************************************************************
 alias1      3 **************************************************************
 user2       2 *****************************************
 % churn with .hgchurn
+skipping malformed alias: not-an-alias
 alias3      3 **************************************************************
 alias1      3 **************************************************************
 user2       2 *****************************************