diff --git a/ChangeLog b/ChangeLog
index 4104d244cc..ff5ae43c38 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Jun 13 00:45:06 2015  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
+
+	* lib/prime.rb: Fix with_object with no block given
+
 Sat Jun 13 00:44:59 2015  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
 
 	* lib/prime.rb: Have with_index accept an offset parameter.
diff --git a/lib/prime.rb b/lib/prime.rb
index 757538db79..1eed28d914 100644
--- a/lib/prime.rb
+++ b/lib/prime.rb
@@ -281,7 +281,7 @@ class Prime
 
     # see +Enumerator+#with_object.
     def with_object(obj)
-      return enum_for(:with_object) unless block_given?
+      return enum_for(:with_object, obj) unless block_given?
       each do |prime|
         yield prime, obj
       end
diff --git a/test/test_prime.rb b/test/test_prime.rb
index 5975336023..d4f056466f 100644
--- a/test/test_prime.rb
+++ b/test/test_prime.rb
@@ -97,6 +97,15 @@ class TestPrime < Test::Unit::TestCase
     end
   end
 
+  def test_enumerator_with_object
+    object = Object.new
+    enum = Prime.each
+    enum.with_object(object).each do |p, o|
+      assert_equal object, o
+      break
+    end
+  end
+
   def test_default_instance_does_not_have_compatibility_methods
     assert !Prime.instance.respond_to?(:succ)
     assert !Prime.instance.respond_to?(:next)