diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index e4a2a11..ab3c9cf 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -135,9 +135,15 @@ class ApplicationController < ActionController::Base
     plugins.each do |plugin|
       filters = plugin.send(self.class.name.underscore + '_filters')
       filters = [filters] if !filters.kind_of?(Array)
+      controller_filters = self.class.filter_chain.map {|c| c.method }
       filters.each do |plugin_filter|
-        self.class.send(plugin_filter[:type], plugin.class.name.underscore + '_' + plugin_filter[:method_name], (plugin_filter[:options] || {}))
-        self.class.send(:define_method, plugin.class.name.underscore + '_' + plugin_filter[:method_name], plugin_filter[:block])
+        filter_method = plugin.class.name.underscore.gsub('/','_') + '_' + plugin_filter[:method_name]
+        unless controller_filters.include?(filter_method)
+          self.class.send(plugin_filter[:type], filter_method, (plugin_filter[:options] || {}))
+          self.class.send(:define_method, filter_method) do
+            instance_eval(&plugin_filter[:block]) if environment.plugin_enabled?(plugin.class)
+          end
+        end
       end
     end
   end
diff --git a/test/functional/application_controller_test.rb b/test/functional/application_controller_test.rb
index 49d09a2..a277dbb 100644
--- a/test/functional/application_controller_test.rb
+++ b/test/functional/application_controller_test.rb
@@ -500,4 +500,46 @@ class ApplicationControllerTest < ActionController::TestCase
     end
 
   end
+
+  should 'do not duplicate plugin filters' do
+
+    class FilterPlugin < Noosfero::Plugin
+      def test_controller_filters
+        { :type => 'before_filter',
+          :method_name => 'filter_plugin',
+          :options => {:only => 'some_method'},
+          :block => lambda {} }
+      end
+    end
+
+    Noosfero::Plugin::Manager.any_instance.stubs(:enabled_plugins).returns([FilterPlugin.new])
+
+    get :index
+    get :index
+    assert_equal 1, @controller.class.filter_chain.select{|c| c.method == 'application_controller_test_filter_plugin_filter_plugin'}.count
+  end
+
+  should 'do not call plugin filter block on a environment that this plugin is not enabled' do
+
+    class OtherFilterPlugin < Noosfero::Plugin
+      def test_controller_filters
+        { :type => 'before_filter',
+          :method_name => 'filter_plugin',
+          :options => {:only => 'some_method'},
+          :block => lambda {'plugin block called'} }
+      end
+    end
+
+    environment1 = fast_create(Environment, :name => 'test environment')
+    environment1.enable_plugin(OtherFilterPlugin.name)
+    environment2 = fast_create(Environment, :name => 'other test environment')
+
+    @controller.stubs(:environment).returns(environment1)
+    get :index
+    assert_equal 'plugin block called', @controller.application_controller_test_other_filter_plugin_filter_plugin
+
+    @controller.stubs(:environment).returns(environment2)
+    assert_equal nil, @controller.application_controller_test_other_filter_plugin_filter_plugin
+  end
+
 end
--
libgit2 0.21.2