diff --git a/activerecord/lib/active_record/associations/has_many_association.rb b/activerecord/lib/active_record/associations/has_many_association.rb
index 660e005348..d00ac96540 100644
--- a/activerecord/lib/active_record/associations/has_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_association.rb
@@ -114,7 +114,7 @@ module ActiveRecord
             begin
               if !loaded?
                 if @target.is_a?(Array) && @target.any?
-                  @target = find_target + @target
+                  @target = (find_target + @target).uniq
                 else
                   @target = find_target
                 end
diff --git a/activerecord/test/associations_test.rb b/activerecord/test/associations_test.rb
index 4c8d169566..4d8817568f 100755
--- a/activerecord/test/associations_test.rb
+++ b/activerecord/test/associations_test.rb
@@ -460,6 +460,14 @@ class HasManyAssociationsTest < Test::Unit::TestCase
     assert_equal 2, companies(:first_firm).clients_of_firm(true).size # checking using the db
     assert_equal natural, companies(:first_firm).clients_of_firm.last
   end
+
+  def test_adding_using_create
+    first_firm = companies(:first_firm)
+    assert_equal 2, first_firm.plain_clients.size
+    natural = first_firm.plain_clients.create(:name => "Natural Company")
+    assert_equal 3, first_firm.plain_clients.length
+    assert_equal 3, first_firm.plain_clients.size
+  end
   
   def test_adding_a_mismatch_class
     assert_raises(ActiveRecord::AssociationTypeMismatch) { companies(:first_firm).clients_of_firm << nil }