diff --git a/cryptography/hazmat/backends/multibackend.py b/cryptography/hazmat/backends/multibackend.py
index 86cded8..2338568 100644
--- a/cryptography/hazmat/backends/multibackend.py
+++ b/cryptography/hazmat/backends/multibackend.py
@@ -16,12 +16,13 @@
 from cryptography import utils
 from cryptography.exceptions import UnsupportedAlgorithm, _Reasons
 from cryptography.hazmat.backends.interfaces import (
-    CipherBackend, DSABackend, HMACBackend, HashBackend, PBKDF2HMACBackend,
-    RSABackend
+    CipherBackend, CMACBackend, DSABackend, HMACBackend, HashBackend,
+    PBKDF2HMACBackend, RSABackend
 )
 
 
 @utils.register_interface(CipherBackend)
+@utils.register_interface(CMACBackend)
 @utils.register_interface(HashBackend)
 @utils.register_interface(HMACBackend)
 @utils.register_interface(PBKDF2HMACBackend)
@@ -156,3 +157,11 @@
             return b.generate_dsa_private_key(parameters)
         raise UnsupportedAlgorithm("DSA is not supported by the backend",
                                    _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM)
+
+    def cmac_supported(self):
+        for b in self._filtered_backends(CMACBackend):
+            return b.cmac_supported()
+
+    def create_cmac_ctx(self, algorithm):
+        for b in self._filtered_backends(CMACBackend):
+            return b.create_cmac_ctx(algorithm)