diff --git a/lib/webrick/httpresponse.rb b/lib/webrick/httpresponse.rb
index 0d36c07..ce72b3f 100644
--- a/lib/webrick/httpresponse.rb
+++ b/lib/webrick/httpresponse.rb
@@ -202,7 +202,7 @@ module WEBrick
       if @header['connection'] == "close"
          @keep_alive = false
       elsif keep_alive?
-        if chunked? || @header['content-length']
+        if chunked? || @header['content-length'] || @status == 304 || @status == 204
           @header['connection'] = "Keep-Alive"
         else
           msg = "Could not determine content-length of response body. Set content-length of the response or set Response#chunked = true"
diff --git a/test/webrick/test_httpresponse.rb b/test/webrick/test_httpresponse.rb
new file mode 100644
index 0000000..3967e2c
--- /dev/null
+++ b/test/webrick/test_httpresponse.rb
@@ -0,0 +1,46 @@
+require "webrick"
+require "minitest/autorun"
+
+module WEBrick
+  class TestHTTPResponse < MiniTest::Unit::TestCase
+    class FakeLogger
+      attr_reader :messages
+
+      def initialize
+        @messages = []
+      end
+
+      def warn msg
+        @messages << msg
+      end
+    end
+
+    def test_304_does_not_log_warning
+      logger          = FakeLogger.new
+      config          = Config::HTTP
+      config[:Logger] = logger
+
+      res             = HTTPResponse.new config
+      res.status      = 304
+      res.keep_alive  = true
+
+      res.setup_header
+
+      assert_equal 0, logger.messages.length
+    end
+
+    def test_204_does_not_log_warning
+      logger          = FakeLogger.new
+      config          = Config::HTTP
+      config[:Logger] = logger
+
+      res             = HTTPResponse.new config
+      res.status      = 204
+      res.keep_alive  = true
+
+      res.setup_header
+
+      assert_equal 0, logger.messages.length
+    end
+  end
+end