diff --git a/ChangeLog b/ChangeLog
index f5b97353f8..91f0672943 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+Sun Sep 27 08:16:35 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/ostruct.rb (delete_field): do not raise NameError for
+	  existing keys.  [Fix GH-1033]
+
+Sun Sep 27 08:16:20 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/ostruct.rb (delete_field): do not raise NameError for
+	  existing keys.  [Fix GH-1033]
+
 Sun Sep 27 00:34:31 2015  Zachary Scott  <zzak@ruby-lang.org>
 
         * lib/ostruct.rb: Move method definitions for getter/setter to be lazy
diff --git a/lib/ostruct.rb b/lib/ostruct.rb
index eeea22042c..a48ae9af05 100644
--- a/lib/ostruct.rb
+++ b/lib/ostruct.rb
@@ -220,8 +220,13 @@ class OpenStruct
   #
   def delete_field(name)
     sym = name.to_sym
-    singleton_class.__send__(:remove_method, sym, "#{sym}=")
-    @table.delete sym
+    begin
+      singleton_class.__send__(:remove_method, sym, "#{sym}=")
+    rescue NameError
+    end
+    @table.delete(sym) do
+      raise NameError.new("no field `#{sym}' in #{self}", sym)
+    end
   end
 
   InspectKey = :__inspect_key__ # :nodoc: