diff --git a/setup.py b/setup.py
index ab1ad99..736fa21 100644
--- a/setup.py
+++ b/setup.py
@@ -430,6 +430,8 @@
         exts.append( Extension("_bytesio", ["_bytesio.c"]) )
         # atexit
         exts.append( Extension("atexit", ["atexitmodule.c"]) )
+        # _json speedups
+        exts.append( Extension("_json", ["_json.c"]) )
         # Python C API test module
         exts.append( Extension('_testcapi', ['_testcapimodule.c']) )
         # profiler (_lsprof is for cProfile.py)