diff --git a/app/models/spree/order_populator_decorator.rb b/app/models/spree/order_populator_decorator.rb
index 5afd6e1551..315a989e64 100644
--- a/app/models/spree/order_populator_decorator.rb
+++ b/app/models/spree/order_populator_decorator.rb
@@ -33,7 +33,7 @@ Spree::OrderPopulator.class_eval do
     if quantity > 0
       if check_stock_levels(variant, quantity) &&
           check_distribution_provided_for(variant) &&
-          check_variant_available_under_distributor(variant)
+          check_variant_available_under_distribution(variant)
 
         @order.add_variant(variant, quantity, currency)
       end
@@ -84,11 +84,11 @@ Spree::OrderPopulator.class_eval do
     distribution_provided
   end
 
-  def check_variant_available_under_distributor(variant)
-    if Enterprise.distributing_product(variant.product).include? @distributor
+  def check_variant_available_under_distribution(variant)
+    if DistributionChangeValidator.new(@order).variants_available_for_distribution(@distributor, @order_cycle).include? variant
       return true
     else
-      errors.add(:base, "That product is not available from the chosen distributor.")
+      errors.add(:base, "That product is not available from the chosen distributor or order cycle.")
       return false
     end
   end
diff --git a/spec/controllers/orders_controller_spec.rb b/spec/controllers/orders_controller_spec.rb
index a3dc31cc9e..50afbbb102 100644
--- a/spec/controllers/orders_controller_spec.rb
+++ b/spec/controllers/orders_controller_spec.rb
@@ -32,6 +32,61 @@ describe Spree::OrdersController do
   end
 
 
+  describe "adding a product to the cart with a distribution combination that can't service the existing cart" do
+    before do
+      @request.env["HTTP_REFERER"] = 'http://test.host/'
+    end
+
+    it "produces an error when the distributor does not distribute the product" do
+      # Given two products with different distributors
+      d1 = create(:distributor_enterprise)
+      d2 = create(:distributor_enterprise)
+      p1 = create(:product, :price => 12.34)
+      p2 = create(:product, :price => 23.45)
+      oc1 = create(:simple_order_cycle, :distributors => [d1], :variants => [p1.master])
+      oc2 = create(:simple_order_cycle, :distributors => [d2], :variants => [p2.master])
+
+      # When I add the first to my cart
+      expect do
+        spree_post :populate, variants: {p1.master.id => 1}, distributor_id: d1.id, order_cycle_id: oc1.id
+        response.should redirect_to spree.cart_path
+      end.to change(self, :num_items_in_cart).by(1)
+
+      # And I attempt to add the second, then the product should not be added to my cart
+      expect do
+        spree_post :populate, variants: {p2.master.id => 1}, distributor_id: d1.id, order_cycle_id: oc1.id
+        response.should redirect_to :back
+      end.to change(self, :num_items_in_cart).by(0)
+
+      # And I should see an error
+      flash[:error].should == "That product is not available from the chosen distributor or order cycle."
+    end
+
+    it "produces an error when the order cycle does not distribute the product" do
+      # Given two products with the same distributor but different order cycles
+      d = create(:distributor_enterprise)
+      p1 = create(:product, :price => 12.34)
+      p2 = create(:product, :price => 23.45)
+      oc1 = create(:simple_order_cycle, :distributors => [d], :variants => [p1.master])
+      oc2 = create(:simple_order_cycle, :distributors => [d], :variants => [p2.master])
+
+      # When I add the first to my cart
+      expect do
+        spree_post :populate, variants: {p1.master.id => 1}, distributor_id: d.id, order_cycle_id: oc1.id
+        response.should redirect_to spree.cart_path
+      end.to change(self, :num_items_in_cart).by(1)
+
+      # And I attempt to add the second, then the product should not be added to my cart
+      expect do
+        spree_post :populate, variants: {p2.master.id => 1}, distributor_id: d.id, order_cycle_id: oc1.id
+        response.should redirect_to :back
+      end.to change(self, :num_items_in_cart).by(0)
+
+      # And I should see an error
+      flash[:error].should == "That product is not available from the chosen distributor or order cycle."
+    end
+  end
+
   context "adding a group buy product to the cart" do
     it "sets a variant attribute for the max quantity" do
       distributor_product = create(:distributor_enterprise)
@@ -46,4 +101,12 @@ describe Spree::OrdersController do
       end.to change(Spree::LineItem, :count).by(1)
     end
   end
+
+
+  private
+
+  def num_items_in_cart
+    Spree::Order.last.andand.line_items.andand.count || 0
+  end
+
 end
diff --git a/spec/models/order_populator_spec.rb b/spec/models/order_populator_spec.rb
index d78f46c496..de64db40ab 100644
--- a/spec/models/order_populator_spec.rb
+++ b/spec/models/order_populator_spec.rb
@@ -70,7 +70,7 @@ module Spree
 
         op.should_receive(:check_stock_levels).with(variant, quantity).and_return(true)
         op.should_receive(:check_distribution_provided_for).with(variant).and_return(true)
-        op.should_receive(:check_variant_available_under_distributor).with(variant).
+        op.should_receive(:check_variant_available_under_distribution).with(variant).
           and_return(true)
         order.should_receive(:add_variant).with(variant, quantity, currency)
 
@@ -120,20 +120,22 @@ module Spree
         let(:product) { double(:product) }
         let(:variant) { double(:variant, product: product) }
 
-        it "is available if the distributor is distributing this product" do
-          op.instance_eval { @distributor = 123 }
-          Enterprise.should_receive(:distributing_product).with(variant.product).and_return [123]
-
-          op.send(:check_variant_available_under_distributor, variant).should be_true
+        it "delegates to DistributionChangeValidator, returning true when available" do
+          dcv = double(:dcv)
+          dcv.should_receive(:variants_available_for_distribution).with(123, 234).and_return([variant])
+          DistributionChangeValidator.should_receive(:new).with(order).and_return(dcv)
+          op.instance_eval { @distributor = 123; @order_cycle = 234 }
+          op.send(:check_variant_available_under_distribution, variant).should be_true
           op.errors.should be_empty
         end
 
-        it "returns false and errors otherwise" do
-          op.instance_eval { @distributor = 123 }
-          Enterprise.should_receive(:distributing_product).with(variant.product).and_return [456]
-
-          op.send(:check_variant_available_under_distributor, variant).should be_false
-          op.errors.to_a.should == ["That product is not available from the chosen distributor."]
+        it "delegates to DistributionChangeValidator, returning false and erroring otherwise" do
+          dcv = double(:dcv)
+          dcv.should_receive(:variants_available_for_distribution).with(123, 234).and_return([])
+          DistributionChangeValidator.should_receive(:new).with(order).and_return(dcv)
+          op.instance_eval { @distributor = 123; @order_cycle = 234 }
+          op.send(:check_variant_available_under_distribution, variant).should be_false
+          op.errors.to_a.should == ["That product is not available from the chosen distributor or order cycle."]
         end
       end
     end