diff --git a/.ci/requirements.txt b/.ci/requirements.txt
index 9dbf98c..e560a65 100644
--- a/.ci/requirements.txt
+++ b/.ci/requirements.txt
@@ -1,3 +1,3 @@
-cython>=0.24
+cython==0.24.1
 aiohttp
 twine
diff --git a/requirements.dev.txt b/requirements.dev.txt
index a5e9c61..bb34904 100644
--- a/requirements.dev.txt
+++ b/requirements.dev.txt
@@ -1,2 +1,2 @@
-Cython>=0.24
+Cython==0.24.1
 Sphinx>=1.4.1