diff --git a/requirements.d/development.txt b/requirements.d/development.txt
index 5805cb4a..88535435 100644
--- a/requirements.d/development.txt
+++ b/requirements.d/development.txt
@@ -7,4 +7,4 @@ pytest
 pytest-xdist
 pytest-cov
 pytest-benchmark
-Cython
+Cython!=0.27