diff --git a/lib/mongo_mapper/plugins/associations/collection.rb b/lib/mongo_mapper/plugins/associations/collection.rb
index <HASH>..<HASH> 100644
--- a/lib/mongo_mapper/plugins/associations/collection.rb
+++ b/lib/mongo_mapper/plugins/associations/collection.rb
@@ -12,6 +12,11 @@ module MongoMapper
           end
         end
 
+        def include?(*args)
+          load_target
+          target.include?(*args)
+        end
+
         def reset
           super
           target = []
diff --git a/test/functional/associations/test_many_documents_proxy.rb b/test/functional/associations/test_many_documents_proxy.rb
index <HASH>..<HASH> 100644
--- a/test/functional/associations/test_many_documents_proxy.rb
+++ b/test/functional/associations/test_many_documents_proxy.rb
@@ -307,6 +307,16 @@ class ManyDocumentsProxyTest < Test::Unit::TestCase
       @project2.save
     end
 
+    context "include?" do
+      should "return true if in association" do
+        @project1.statuses.should include(@brand_new)
+      end
+
+      should "return false if not in association" do
+        @project1.statuses.should_not include(@in_progress)
+      end
+    end
+
     context "dynamic finders" do
       should "work with single key" do
         @project1.statuses.find_by_name('New').should == @brand_new
Ensure that include? works on many doc associations.