diff --git a/lib/fog/aws/acs.rb b/lib/fog/aws/acs.rb
index 849cf46be..7195cd939 100644
--- a/lib/fog/aws/acs.rb
+++ b/lib/fog/aws/acs.rb
@@ -29,11 +29,11 @@ module Fog
 
       #request :describe_events
 
-      # model_path 'fog/aws/models/acs'
+      model_path 'fog/aws/models/acs'
       # model :server
       # collection :servers
-      # model :security_group
-      # collection :security_groups
+      model :security_group
+      collection :security_groups
       # model :parameter_group
       # collection :parameter_groups
 
@@ -96,8 +96,20 @@ module Fog
               :parser     => parser
             })
           rescue Excon::Errors::HTTPStatusError => error
-            # TODO: handle not found errors
-            raise
+            if match = error.message.match(/<Code>(.*)<\/Code>/m)
+              case match[1]
+              when 'CacheSecurityGroupNotFound'
+                raise Fog::AWS::ACS::NotFound
+              when 'CacheSecurityGroupAlreadyExists'
+                raise Fog::AWS::ACS::IndentifierTaken
+              when 'InvalidParameterValue'
+                raise Fog::AWS::ACE::InvalidInstance
+              else
+                raise
+              end
+            else
+              raise
+            end
           end
 
           response
diff --git a/lib/fog/aws/models/acs/security_group.rb b/lib/fog/aws/models/acs/security_group.rb
new file mode 100644
index 000000000..7357518a6
--- /dev/null
+++ b/lib/fog/aws/models/acs/security_group.rb
@@ -0,0 +1,42 @@
+require 'fog/core/model'
+
+module Fog
+  module AWS
+    class ACS
+
+      class SecurityGroup < Fog::Model
+
+        identity :id, :aliases => 'CacheSecurityGroupName'
+        attribute :description, :aliases => 'CacheSecurityGroupDescription'
+        attribute :ec2_security_group, :aliases => 'EC2SecurityGroups', :type => :array
+        attribute :owner_id, :aliases => 'OwnerId'
+
+        def ready?
+          ec2_security_groups.all?{|ingress| ingress['Status'] == 'authorized'}
+        end
+
+        def destroy
+          requires :id
+          connection.delete_cache_security_group(id)
+          true
+        end
+
+        def save
+          requires :id
+          requires :description
+          connection.create_cache_security_group(id, description)
+        end
+
+        def authorize_ec2_group(group_name, group_owner_id=owner_id)
+          connection.authorize_ec2_security_group(id, group_name, group_owner_id)
+        end
+
+        def revoke_ec2_group(group_name, group_owner_id=owner_id)
+          connection.revoke_ec2_security_group(id, group_name, group_owner_id)
+        end
+
+      end
+
+    end
+  end
+end
diff --git a/lib/fog/aws/models/acs/security_groups.rb b/lib/fog/aws/models/acs/security_groups.rb
new file mode 100644
index 000000000..cf06dbc1a
--- /dev/null
+++ b/lib/fog/aws/models/acs/security_groups.rb
@@ -0,0 +1,26 @@
+require 'fog/core/collection'
+require 'fog/aws/models/acs/security_group'
+
+module Fog
+  module AWS
+    class ACS
+
+      class SecurityGroups < Fog::Collection
+        model Fog::AWS::ACS::SecurityGroup
+
+        def all
+          data = connection.describe_cache_security_groups.body['CacheSecurityGroups']
+          load(data)
+        end
+
+        def get(identity)
+          data = connection.describe_cache_security_groups('CacheSecurityGroupName' => identity).body['CacheSecurityGroups'].first
+          new(data)
+        rescue Fog::AWS::ACS::NotFound
+          nil
+        end
+      end
+
+    end
+  end
+end
diff --git a/tests/aws/models/acs/security_groups.rb b/tests/aws/models/acs/security_groups.rb
new file mode 100644
index 000000000..efe9a6258
--- /dev/null
+++ b/tests/aws/models/acs/security_groups.rb
@@ -0,0 +1,14 @@
+Shindo.tests('AWS::ACS | security groups', ['aws', 'acs']) do
+  group_name = 'fog-test'
+  description = 'Fog Test'
+
+  pending if Fog.mocking?
+
+  model_tests(AWS[:acs].security_groups, {:id => group_name, :description => description}, false) do
+    # TODO:
+    # test authorize_ec2_group
+    # test revoke_ec2_group
+  end
+
+  collection_tests(AWS[:acs].security_groups, {:id => group_name, :description => description}, false)
+end