diff --git a/dev-python/cython/cython-0.22.ebuild b/dev-python/cython/cython-0.22.ebuild
index bf1dad9c1474c..6b9a46affdfcb 100644
--- a/dev-python/cython/cython-0.22.ebuild
+++ b/dev-python/cython/cython-0.22.ebuild
@@ -5,6 +5,7 @@
 EAPI=5
 
 PYTHON_COMPAT=( python{2_7,3_3,3_4} )
+PYTHON_REQ_USE="threads(+)"
 
 inherit distutils-r1 flag-o-matic toolchain-funcs
 
diff --git a/dev-python/cython/cython-0.23.2.ebuild b/dev-python/cython/cython-0.23.2.ebuild
index ea5a078b2b07f..b7bdcb76b9f81 100644
--- a/dev-python/cython/cython-0.23.2.ebuild
+++ b/dev-python/cython/cython-0.23.2.ebuild
@@ -5,6 +5,7 @@
 EAPI=5
 
 PYTHON_COMPAT=( python2_7 python3_{3,4} )
+PYTHON_REQ_USE="threads(+)"
 
 inherit distutils-r1 flag-o-matic toolchain-funcs
 
diff --git a/dev-python/cython/cython-0.23.3.ebuild b/dev-python/cython/cython-0.23.3.ebuild
index bc79b4d9f2878..ba3f159b41e0f 100644
--- a/dev-python/cython/cython-0.23.3.ebuild
+++ b/dev-python/cython/cython-0.23.3.ebuild
@@ -5,6 +5,7 @@
 EAPI=5
 
 PYTHON_COMPAT=( python2_7 python3_{3,4,5} )
+PYTHON_REQ_USE="threads(+)"
 
 inherit distutils-r1 flag-o-matic toolchain-funcs
 
diff --git a/dev-python/cython/cython-0.23.4.ebuild b/dev-python/cython/cython-0.23.4.ebuild
index bc79b4d9f2878..ba3f159b41e0f 100644
--- a/dev-python/cython/cython-0.23.4.ebuild
+++ b/dev-python/cython/cython-0.23.4.ebuild
@@ -5,6 +5,7 @@
 EAPI=5
 
 PYTHON_COMPAT=( python2_7 python3_{3,4,5} )
+PYTHON_REQ_USE="threads(+)"
 
 inherit distutils-r1 flag-o-matic toolchain-funcs