diff --git a/setup.py b/setup.py
index 822522a..6448696 100644
--- a/setup.py
+++ b/setup.py
@@ -48,6 +48,11 @@ if __name__=="__main__":
     from obidistutils.core import CEXES
     from obidistutils.core import FILES
     
+    # Produce annotated html files
+    import Cython.Compiler.Options
+    Cython.Compiler.Options.annotate = True
+
+    
     setup(name=PACKAGE,
           description=DESCRIPTION,
           classifiers=classifiers,