diff --git a/pykwalify/rule.py b/pykwalify/rule.py
index f044b69..666461b 100644
--- a/pykwalify/rule.py
+++ b/pykwalify/rule.py
@@ -1149,7 +1149,7 @@ def init_mapping_value(self, v, rule, path):
                 v = {}
 
             # Check if this is a regex rule. Handle specially
-            if k.startswith("regex;") or k.startswith("re;"):
+            if str(k).startswith("regex;") or str(k).startswith("re;"):
                 log.debug(u"Found regex map rule")
                 regex = k.split(";", 1)
                 if len(regex) != 2:
diff --git a/tests/files/success/test_mapping.yaml b/tests/files/success/test_mapping.yaml
index 22656f9..a300843 100644
--- a/tests/files/success/test_mapping.yaml
+++ b/tests/files/success/test_mapping.yaml
@@ -321,3 +321,17 @@ schema:
       mapping:
         regex;(.+):
           type: str
+---
+name: mapping20
+desc: Test mapping with integer keys
+data:
+  test:
+    0: test
+schema:
+  type: map
+  mapping:
+    test:
+      type: map
+      mapping:
+        0:
+          type: str