diff --git a/codec/src/main/java/io/netty/handler/codec/serialization/CompatibleObjectEncoder.java b/codec/src/main/java/io/netty/handler/codec/serialization/CompatibleObjectEncoder.java
index 81543b870c..db97def754 100644
--- a/codec/src/main/java/io/netty/handler/codec/serialization/CompatibleObjectEncoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/serialization/CompatibleObjectEncoder.java
@@ -35,10 +35,6 @@ import java.io.Serializable;
  * {@link ObjectInputStream} and {@link ObjectOutputStream}.
  */
 public class CompatibleObjectEncoder extends MessageToByteEncoder<Serializable> {
-
-    private static final AttributeKey<ObjectOutputStream> OOS =
-            AttributeKey.valueOf(CompatibleObjectEncoder.class, "OOS");
-
     private final int resetInterval;
     private int writtenObjects;
 
@@ -77,17 +73,8 @@ public class CompatibleObjectEncoder extends MessageToByteEncoder<Serializable>
 
     @Override
     protected void encode(ChannelHandlerContext ctx, Serializable msg, ByteBuf out) throws Exception {
-        Attribute<ObjectOutputStream> oosAttr = ctx.attr(OOS);
-        ObjectOutputStream oos = oosAttr.get();
-        if (oos == null) {
-            oos = newObjectOutputStream(new ByteBufOutputStream(out));
-            ObjectOutputStream newOos = oosAttr.setIfAbsent(oos);
-            if (newOos != null) {
-                oos = newOos;
-            }
-        }
-
-        synchronized (oos) {
+        ObjectOutputStream oos = newObjectOutputStream(new ByteBufOutputStream(out));
+        try {
             if (resetInterval != 0) {
                 // Resetting will prevent OOM on the receiving side.
                 writtenObjects ++;
@@ -98,6 +85,8 @@ public class CompatibleObjectEncoder extends MessageToByteEncoder<Serializable>
 
             oos.writeObject(msg);
             oos.flush();
+        } finally {
+            oos.close();
         }
     }
 }
diff --git a/codec/src/test/java/io/netty/handler/codec/serialization/CompatibleObjectEncoderTest.java b/codec/src/test/java/io/netty/handler/codec/serialization/CompatibleObjectEncoderTest.java
new file mode 100644
index 0000000000..629a323acb
--- /dev/null
+++ b/codec/src/test/java/io/netty/handler/codec/serialization/CompatibleObjectEncoderTest.java
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2016 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.serialization;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufInputStream;
+import io.netty.channel.embedded.EmbeddedChannel;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.Serializable;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class CompatibleObjectEncoderTest {
+    @Test
+    public void testMultipleEncodeReferenceCount() throws IOException, ClassNotFoundException {
+        EmbeddedChannel channel = new EmbeddedChannel(new CompatibleObjectEncoder());
+        testEncode(channel, new TestSerializable(6, 8));
+        testEncode(channel, new TestSerializable(10, 5));
+        testEncode(channel, new TestSerializable(1, 5));
+        assertFalse(channel.finishAndReleaseAll());
+    }
+
+    private static void testEncode(EmbeddedChannel channel, TestSerializable original)
+            throws IOException, ClassNotFoundException {
+        channel.writeOutbound(original);
+        Object o = channel.readOutbound();
+        ByteBuf buf = (ByteBuf) o;
+        ObjectInputStream ois = new ObjectInputStream(new ByteBufInputStream(buf));
+        try {
+            assertEquals(original, ois.readObject());
+        } finally {
+            buf.release();
+            ois.close();
+        }
+    }
+
+    private static final class TestSerializable implements Serializable {
+        public final int x;
+        public final int y;
+
+        TestSerializable(int x, int y) {
+            this.x = x;
+            this.y = y;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (!(o instanceof TestSerializable)) {
+                return false;
+            }
+            TestSerializable rhs = (TestSerializable) o;
+            return x == rhs.x && y == rhs.y;
+        }
+
+        @Override
+        public int hashCode() {
+            return 31 * (31 + x) + y;
+        }
+    }
+}