diff --git a/CHANGELOG.rdoc b/CHANGELOG.rdoc
index 6be73e5..0843027 100644
--- a/CHANGELOG.rdoc
+++ b/CHANGELOG.rdoc
@@ -1,3 +1,5 @@
+* Append aliased actions (don't overwrite them) - see issue #20
+
 * Adding custom message argument to unauthorized! method (thanks tjwallace) - see issue #18
 
 
diff --git a/lib/cancan/ability.rb b/lib/cancan/ability.rb
index 4783e7b..1fab685 100644
--- a/lib/cancan/ability.rb
+++ b/lib/cancan/ability.rb
@@ -156,7 +156,8 @@ module CanCan
     # This way one can use params[:action] in the controller to determine the permission.
     def alias_action(*args)
       target = args.pop[:to]
-      aliased_actions[target] = args
+      aliased_actions[target] ||= []
+      aliased_actions[target] += args
     end
     
     private
diff --git a/spec/cancan/ability_spec.rb b/spec/cancan/ability_spec.rb
index 3377e97..e6178a1 100644
--- a/spec/cancan/ability_spec.rb
+++ b/spec/cancan/ability_spec.rb
@@ -2,9 +2,8 @@ require File.dirname(__FILE__) + '/../spec_helper'
 
 describe CanCan::Ability do
   before(:each) do
-    @ability_class = Class.new
-    @ability_class.send(:include, CanCan::Ability)
-    @ability = @ability_class.new
+    @ability = Object.new
+    @ability.extend(CanCan::Ability)
   end
   
   it "should be able to :read anything" do
@@ -123,4 +122,14 @@ describe CanCan::Ability do
     @ability.can?(:read, 3).should be_true
     @ability.can?(:read, 123).should be_false
   end
+  
+  it "should append aliased actions" do
+    @ability.alias_action :update, :to => :modify
+    @ability.alias_action :destroy, :to => :modify
+    @ability.can :modify, :all do |object_class, object|
+      :modify_called
+    end
+    @ability.can?(:update, 123).should == :modify_called
+    @ability.can?(:destroy, 123).should == :modify_called
+  end
 end