diff --git a/autotools/build-rpc b/autotools/build-rpc
index 222619f2ab41acde89ba029dc33c2c658d45c752..576dd0d282035a2a96800a33b20d56750b730ce8 100755
--- a/autotools/build-rpc
+++ b/autotools/build-rpc
@@ -187,6 +187,12 @@ def main():
     assert module.SINGLE == _SINGLE
     assert module.MULTI == _MULTI
 
+    dups = utils.FindDuplicates(itertools.chain(*map(lambda value: value.keys(),
+                                                     module.CALLS.values())))
+    if dups:
+      raise Exception("Found duplicate RPC definitions for '%s'" %
+                      utils.CommaJoin(sorted(dups)))
+
     for (clsname, calls) in module.CALLS.items():
       _WriteBaseClass(sw, clsname, calls.values())