diff --git a/moto/redshift/models.py b/moto/redshift/models.py
index 6f1a89675..d40ea0871 100644
--- a/moto/redshift/models.py
+++ b/moto/redshift/models.py
@@ -25,7 +25,6 @@ class Cluster(object):
         self.master_username = master_username
         self.master_user_password = master_user_password
         self.db_name = db_name if db_name else "dev"
-        self.cluster_security_groups = cluster_security_groups
         self.vpc_security_group_ids = vpc_security_group_ids
         self.cluster_subnet_group_name = cluster_subnet_group_name
         self.cluster_parameter_group_name = cluster_parameter_group_name
@@ -38,6 +37,11 @@ class Cluster(object):
         self.automated_snapshot_retention_period = automated_snapshot_retention_period if automated_snapshot_retention_period else 1
         self.preferred_maintenance_window = preferred_maintenance_window if preferred_maintenance_window else "Mon:03:00-Mon:03:30"
 
+        if cluster_security_groups:
+            self.cluster_security_groups = cluster_security_groups
+        else:
+            self.cluster_security_groups = ["Default"]
+
         if availability_zone:
             self.availability_zone = availability_zone
         else:
@@ -140,7 +144,9 @@ class RedshiftBackend(BaseBackend):
     def __init__(self, ec2_backend):
         self.clusters = {}
         self.subnet_groups = {}
-        self.security_groups = {}
+        self.security_groups = {
+            "Default": SecurityGroup("Default", "Default Redshift Security Group")
+        }
         self.ec2_backend = ec2_backend
 
     def reset(self):
diff --git a/tests/test_redshift/test_redshift.py b/tests/test_redshift/test_redshift.py
index ba5e30065..881c65504 100644
--- a/tests/test_redshift/test_redshift.py
+++ b/tests/test_redshift/test_redshift.py
@@ -41,7 +41,7 @@ def test_create_cluster():
     cluster['NodeType'].should.equal("dw.hs1.xlarge")
     cluster['MasterUsername'].should.equal("username")
     cluster['DBName'].should.equal("my_db")
-    cluster['ClusterSecurityGroups'].should.equal([])
+    cluster['ClusterSecurityGroups'][0]['ClusterSecurityGroupName'].should.equal("Default")
     cluster['VpcSecurityGroups'].should.equal([])
     cluster['ClusterSubnetGroupName'].should.equal(None)
     cluster['AvailabilityZone'].should.equal("us-east-1d")
@@ -94,7 +94,6 @@ def test_default_cluster_attibutes():
     cluster = cluster_response['DescribeClustersResponse']['DescribeClustersResult']['Clusters'][0]
 
     cluster['DBName'].should.equal("dev")
-    # cluster['ClusterSecurityGroups'].should.equal([])
     # cluster['VpcSecurityGroups'].should.equal([])
     cluster['ClusterSubnetGroupName'].should.equal(None)
     assert "us-east-" in cluster['AvailabilityZone']
@@ -326,13 +325,13 @@ def test_delete_cluster_security_group():
 
     groups_response = conn.describe_cluster_security_groups()
     groups = groups_response['DescribeClusterSecurityGroupsResponse']['DescribeClusterSecurityGroupsResult']['ClusterSecurityGroups']
-    groups.should.have.length_of(1)
+    groups.should.have.length_of(2)  # The default group already exists
 
     conn.delete_cluster_security_group("my_security_group")
 
     groups_response = conn.describe_cluster_security_groups()
     groups = groups_response['DescribeClusterSecurityGroupsResponse']['DescribeClusterSecurityGroupsResult']['ClusterSecurityGroups']
-    groups.should.have.length_of(0)
+    groups.should.have.length_of(1)
 
     # Delete invalid id
     conn.delete_cluster_security_group.when.called_with("not-a-security-group").should.throw(ClusterSecurityGroupNotFound)