diff --git a/app/models/rate.rb b/app/models/rate.rb
index c8c0a29..5416215 100644
--- a/app/models/rate.rb
+++ b/app/models/rate.rb
@@ -11,6 +11,7 @@ class Rate < ActiveRecord::Base
   validates_numericality_of :amount
   
   before_save :unlocked?
+  after_save :update_time_entry_cost_cache
   before_destroy :unlocked?
   
   named_scope :history_for_user, lambda { |user, order|
@@ -36,6 +37,10 @@ class Rate < ActiveRecord::Base
   def specific?
     return !self.default?
   end
+
+  def update_time_entry_cost_cache
+    TimeEntry.update_cost_cache(user, project)
+  end
   
   # API to find the Rate for a +user+ on a +project+ at a +date+
   def self.for(user, project = nil, date = Date.today.to_s)
diff --git a/lib/rate_time_entry_patch.rb b/lib/rate_time_entry_patch.rb
index fa93f83..5a2e959 100644
--- a/lib/rate_time_entry_patch.rb
+++ b/lib/rate_time_entry_patch.rb
@@ -17,7 +17,16 @@ module RateTimeEntryPatch
   end
   
   module ClassMethods
-    
+    # Updated the cached cost of all TimeEntries for user and project
+    def update_cost_cache(user, project=nil)
+      c = ARCondition.new
+      c << ["#{TimeEntry.table_name}.user_id = ?", user]
+      c << ["#{TimeEntry.table_name}.project_id = ?", project] if project
+      
+      TimeEntry.all(:conditions => c.conditions).each do |time_entry|
+        time_entry.save_cached_cost
+      end
+    end
   end
   
   module InstanceMethods
@@ -53,6 +62,7 @@ module RateTimeEntryPatch
     end
 
     def save_cached_cost
+      clear_cost_cache
       update_attribute(:cost, cost)
     end
     
diff --git a/test/unit/rate_test.rb b/test/unit/rate_test.rb
index 89bce69..62ec0f5 100644
--- a/test/unit/rate_test.rb
+++ b/test/unit/rate_test.rb
@@ -84,6 +84,28 @@ class RateTest < ActiveSupport::TestCase
     end
   end
 
+  context "after save" do
+    should "recalculate all of the cached cost of all Time Entries for the user" do
+      @user = User.generate!
+      @project = Project.generate!
+      @date = Date.today.to_s
+      @past_date = 1.month.ago.strftime('%Y-%m-%d')
+      @rate = Rate.generate!(:user => @user, :project => @project, :date_in_effect => @date, :amount => 200.0)
+      @time_entry1 = TimeEntry.generate!({:user => @user, :project => @project, :spent_on => @date, :hours => 10.0, :activity => TimeEntryActivity.generate!})
+      @time_entry2 = TimeEntry.generate!({:user => @user, :project => @project, :spent_on => @past_date, :hours => 20.0, :activity => TimeEntryActivity.generate!})
+
+
+      assert_equal 2000.00, @time_entry1.cost
+      assert_equal 0, @time_entry2.cost
+
+      @old_rate = Rate.generate!(:user => @user, :project => @project, :date_in_effect => 2.months.ago.strftime('%Y-%m-%d'), :amount => 10.0)
+
+      assert_equal 2000.00, TimeEntry.find(@time_entry1.id).cost
+      assert_equal 200.00, TimeEntry.find(@time_entry2.id).cost
+    end
+    
+  end
+  
   context '#for' do
     setup do
       @user = User.generate!