diff --git a/csharp/src/ProtocolBuffers.Test/FieldCodecTest.cs b/csharp/src/ProtocolBuffers.Test/FieldCodecTest.cs
new file mode 100644
index 0000000000..e2b8e3ef15
--- /dev/null
+++ b/csharp/src/ProtocolBuffers.Test/FieldCodecTest.cs
@@ -0,0 +1,149 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+
+using System.Collections.Generic;
+using System.IO;
+using Google.Protobuf.TestProtos;
+using NUnit.Framework;
+
+namespace Google.Protobuf
+{
+    public class FieldCodecTest
+    {
+        private static readonly List<ICodecTestData> Codecs = new List<ICodecTestData>
+        {
+            new FieldCodecTestData<bool>(FieldCodec.ForBool(100), true, "Bool"),
+            new FieldCodecTestData<string>(FieldCodec.ForString(100), "sample", "String"),
+            new FieldCodecTestData<ByteString>(FieldCodec.ForBytes(100), ByteString.CopyFrom(1, 2, 3), "Bytes"),
+            new FieldCodecTestData<int>(FieldCodec.ForInt32(100), -1000, "Int32"),
+            new FieldCodecTestData<int>(FieldCodec.ForSInt32(100), -1000, "SInt32"),
+            new FieldCodecTestData<int>(FieldCodec.ForSFixed32(100), -1000, "SFixed32"),
+            new FieldCodecTestData<uint>(FieldCodec.ForUInt32(100), 1234, "UInt32"),
+            new FieldCodecTestData<uint>(FieldCodec.ForFixed32(100), 1234, "Fixed32"),
+            new FieldCodecTestData<long>(FieldCodec.ForInt64(100), -1000, "Int64"),
+            new FieldCodecTestData<long>(FieldCodec.ForSInt64(100), -1000, "SInt64"),
+            new FieldCodecTestData<long>(FieldCodec.ForSFixed64(100), -1000, "SFixed64"),
+            new FieldCodecTestData<ulong>(FieldCodec.ForUInt64(100), 1234, "UInt64"),
+            new FieldCodecTestData<ulong>(FieldCodec.ForFixed64(100), 1234, "Fixed64"),
+            new FieldCodecTestData<float>(FieldCodec.ForFloat(100), 1234.5f, "Float"),
+            new FieldCodecTestData<double>(FieldCodec.ForDouble(100), 1234567890.5d, "Double"),
+            new FieldCodecTestData<ForeignEnum>(
+                FieldCodec.ForEnum(100, t => (int) t, t => (ForeignEnum) t), ForeignEnum.FOREIGN_BAZ, "Enum"),
+            new FieldCodecTestData<ForeignMessage>(
+                FieldCodec.ForMessage(100, ForeignMessage.Parser), new ForeignMessage { C = 10 }, "Message"),
+        };
+
+        [Test, TestCaseSource("Codecs")]
+        public void RoundTrip(ICodecTestData codec)
+        {
+            codec.TestRoundTrip();
+        }
+
+        [Test, TestCaseSource("Codecs")]
+        public void CalculateSize(ICodecTestData codec)
+        {
+            codec.TestCalculateSize();
+        }
+
+        [Test, TestCaseSource("Codecs")]
+        public void DefaultValue(ICodecTestData codec)
+        {
+            codec.TestDefaultValue();
+        }
+
+        public interface ICodecTestData
+        {
+            void TestRoundTrip();
+            void TestCalculateSize();
+            void TestDefaultValue();
+        }
+
+        public class FieldCodecTestData<T> : ICodecTestData
+        {
+            private readonly FieldCodec<T> codec;
+            private readonly T sampleValue;
+            private readonly string name;
+
+            public FieldCodecTestData(FieldCodec<T> codec, T sampleValue, string name)
+            {
+                this.codec = codec;
+                this.sampleValue = sampleValue;
+                this.name = name;
+            }
+
+            public void TestRoundTrip()
+            {
+                var stream = new MemoryStream();
+                var codedOutput = CodedOutputStream.CreateInstance(stream);
+                codec.Write(codedOutput, sampleValue);
+                codedOutput.Flush();
+                stream.Position = 0;
+                var codedInput = CodedInputStream.CreateInstance(stream);
+                uint tag;
+                Assert.IsTrue(codedInput.ReadTag(out tag));
+                Assert.AreEqual(codec.Tag, tag);
+                Assert.AreEqual(sampleValue, codec.Read(codedInput));
+                Assert.IsTrue(codedInput.IsAtEnd);
+            }
+
+            public void TestCalculateSize()
+            {
+                var stream = new MemoryStream();
+                var codedOutput = CodedOutputStream.CreateInstance(stream);
+                codec.Write(codedOutput, sampleValue);
+                codedOutput.Flush();
+                Assert.AreEqual(stream.Position, codec.CalculateSize(sampleValue));
+            }
+
+            public void TestDefaultValue()
+            {
+                var stream = new MemoryStream();
+                var codedOutput = CodedOutputStream.CreateInstance(stream);
+                codec.Write(codedOutput, codec.DefaultValue);
+                codedOutput.Flush();
+                Assert.AreEqual(0, stream.Position);
+                Assert.AreEqual(0, codec.CalculateSize(codec.DefaultValue));
+                if (typeof(T).IsValueType)
+                {
+                    Assert.AreEqual(default(T), codec.DefaultValue);
+                }
+            }
+
+            public string Description { get { return name; } }
+
+            public override string ToString()
+            {
+                return name;
+            }
+        }
+    }
+}
diff --git a/csharp/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj b/csharp/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
index c3fd8ba6a2..e90be51d6d 100644
--- a/csharp/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
+++ b/csharp/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
@@ -75,6 +75,7 @@
     <Compile Include="CodedInputStreamTest.cs" />
     <Compile Include="CodedOutputStreamTest.cs" />
     <Compile Include="EqualityTester.cs" />
+    <Compile Include="FieldCodecTest.cs" />
     <Compile Include="GeneratedMessageTest.cs" />
     <Compile Include="Collections\MapFieldTest.cs" />
     <Compile Include="Collections\RepeatedFieldTest.cs" />
diff --git a/csharp/src/ProtocolBuffers/FieldCodec.cs b/csharp/src/ProtocolBuffers/FieldCodec.cs
index 617af2f62a..4cab9cc407 100644
--- a/csharp/src/ProtocolBuffers/FieldCodec.cs
+++ b/csharp/src/ProtocolBuffers/FieldCodec.cs
@@ -80,7 +80,7 @@ namespace Google.Protobuf
 
         public static FieldCodec<double> ForDouble(uint tag)
         {
-            return new FieldCodec<double>(input => input.ReadFloat(), (output, value) => output.WriteDouble(value), CodedOutputStream.ComputeDoubleSize, tag);
+            return new FieldCodec<double>(input => input.ReadDouble(), (output, value) => output.WriteDouble(value), CodedOutputStream.ComputeDoubleSize, tag);
         }
 
         // Enums are tricky. We can probably use expression trees to build these delegates automatically,