diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 187caa13d0..52f6a04da1 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -1296,7 +1296,7 @@ module ActiveRecord
           end
 
           define_method("#{reflection.name.to_s.singularize}_ids") do
-            if send(reflection.name).loaded?
+            if send(reflection.name).loaded? || reflection.options[:finder_sql]
               send(reflection.name).map(&:id)
             else
               send(reflection.name).all(:select => "#{reflection.quoted_table_name}.#{reflection.klass.primary_key}").map(&:id)
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index 8d97b30c74..59784e1bcb 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -853,6 +853,13 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert !company.clients.loaded?
   end
 
+  def test_get_ids_for_unloaded_finder_sql_associations_loads_them
+    company = companies(:first_firm)
+    assert !company.clients_using_sql.loaded?
+    assert_equal [companies(:second_client).id], company.clients_using_sql_ids
+    assert company.clients_using_sql.loaded?
+  end
+
   def test_assign_ids
     firm = Firm.new("name" => "Apple")
     firm.client_ids = [companies(:first_client).id, companies(:second_client).id]