diff --git a/tests/test_rds.py b/tests/test_rds.py
index 304f725f8..610cfae43 100644
--- a/tests/test_rds.py
+++ b/tests/test_rds.py
@@ -2,6 +2,8 @@
 import troposphere.rds as rds
 from troposphere import If, Parameter, Ref
 
+AWS_NO_VALUE = "AWS::NoValue"
+
 
 class TestRDS(unittest.TestCase):
 
@@ -150,9 +152,16 @@ def test_fail_az_and_multiaz(self):
             MultiAZ=True)
         with self.assertRaisesRegexp(ValueError, "if MultiAZ is set to "):
             i.JSONrepr()
+        i.MultiAZ = "false"
+        i.JSONrepr()
+        i.MultiAZ = "true"
+        with self.assertRaisesRegexp(ValueError, "if MultiAZ is set to "):
+            i.JSONrepr()
+
+        i.MultiAZ = Ref(AWS_NO_VALUE)
+        i.JSONrepr()
 
     def test_az_and_multiaz_funcs(self):
-        AWS_NO_VALUE = "AWS::NoValue"
         db_az = "us-east-1"
         db_multi_az = Parameter("dbmultiaz", Type="String")
         i = rds.DBInstance(
diff --git a/troposphere/rds.py b/troposphere/rds.py
index b6afb627a..0e5342d1c 100644
--- a/troposphere/rds.py
+++ b/troposphere/rds.py
@@ -199,8 +199,7 @@ def validate(self):
         multi_az = self.properties.get('MultiAZ', None)
         if not (isinstance(avail_zone, (AWSHelperFn, nonetype)) and
                 isinstance(multi_az, (AWSHelperFn, nonetype))):
-            if 'AvailabilityZone' in self.properties and \
-                    self.properties.get('MultiAZ', None):
+            if avail_zone and multi_az in [True, 1, '1', 'true', 'True']:
                 raise ValueError("AvailabiltyZone cannot be set on "
                                  "DBInstance if MultiAZ is set to true.")