diff --git a/setup.py b/setup.py
index 04c8ff2..a9258a1 100644
--- a/setup.py
+++ b/setup.py
@@ -155,7 +155,7 @@ def build_extensions(self):
     install_requires=[
         "numpy",
         "scipy",
-        "cython",
+        "Cython",  # not: cython
         "matplotlib",
         "scikit-learn",
       ],