diff --git a/setup.py b/setup.py
index 3e2ab3e..ead5ec4 100644
--- a/setup.py
+++ b/setup.py
@@ -36,6 +36,7 @@
 
 requirements = [
     CFFI_DEPENDENCY,
+    "enum34",
     "pyasn1",
     SIX_DEPENDENCY,
     SETUPTOOLS_DEPENDENCY
diff --git a/src/cryptography/hazmat/backends/openssl/x509.py b/src/cryptography/hazmat/backends/openssl/x509.py
index 8dced83..9f12da0 100644
--- a/src/cryptography/hazmat/backends/openssl/x509.py
+++ b/src/cryptography/hazmat/backends/openssl/x509.py
@@ -16,7 +16,7 @@
 import datetime
 
 from cryptography import utils
-from cryptography.hazmat.primitives import hashes, interfaces
+from cryptography.hazmat.primitives import hashes, interfaces, x509
 
 
 @utils.register_interface(interfaces.X509Certificate)
@@ -53,6 +53,16 @@
         return h.finalize()
 
     @property
+    def version(self):
+        version = self._backend._lib.X509_get_version(self._x509)
+        if version == 0:
+            return x509.X509Version.v1
+        elif version == 2:
+            return x509.X509Version.v3
+        else:
+            raise StandardError("TODO")
+
+    @property
     def serial(self):
         asn1_int = self._backend._lib.X509_get_serialNumber(self._x509)
         assert asn1_int != self._backend._ffi.NULL