diff --git a/cython/setup.py.in b/cython/setup.py.in
index a2ee736c1..043df6b77 100644
--- a/cython/setup.py.in
+++ b/cython/setup.py.in
@@ -7,7 +7,7 @@ setup(
   ext_modules = cythonize(Extension(
     "gtsam",
     sources=["gtsam.pyx"],
-    include_dirs = ["${CMAKE_SOURCE_DIR}",
+    include_dirs = ["${CMAKE_SOURCE_DIR}", "${CMAKE_BINARY_DIR}",
                     "${CMAKE_SOURCE_DIR}/gtsam/3rdparty/Eigen"
                     ] + eigency.get_includes(include_eigen=False),
     libraries = ['gtsam'],