https://github.com/pyca/cryptography/commit/5bea5ca0233be05e09d8c62fdeae86187e73a48e
diff --git a/setup.py b/setup.py
index ead5ec4..32a87ba 100644
--- a/setup.py
+++ b/setup.py
@@ -36,12 +36,14 @@
 
 requirements = [
     CFFI_DEPENDENCY,
-    "enum34",
     "pyasn1",
     SIX_DEPENDENCY,
     SETUPTOOLS_DEPENDENCY
 ]
 
+if sys.version_info < (3, 4):
+    requirements.append("enum34")
+
 # If you add a new dep here you probably need to add it in the tox.ini as well
 test_requirements = [
     "pytest",