3 files changed, 11 insertions, 3 deletions
diff --git a/csharp/src/Google.Protobuf/JsonFormatter.cs b/csharp/src/Google.Protobuf/JsonFormatter.cs
index eb959c9f..cbd9366c 100644
--- a/csharp/src/Google.Protobuf/JsonFormatter.cs
+++ b/csharp/src/Google.Protobuf/JsonFormatter.cs
@@ -237,11 +237,13 @@ namespace Google.Protobuf
                 {
                     writer.Write(PropertySeparator);
                 }
-                WriteString(writer, ToCamelCase(accessor.Descriptor.Name));
+
+                WriteString(writer, accessor.Descriptor.JsonName);
                 writer.Write(NameValueSeparator);
                 WriteValue(writer, value);
+
                 first = false;
-            }            
+            }
             return !first;
         }
 
diff --git a/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs
index c6caaec6..6083f171 100644
--- a/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs
@@ -90,6 +90,12 @@ namespace Google.Protobuf.Reflection
         /// </summary>
         public override string Name { get { return proto.Name; } }
 
+
+        /// <summary>
+        /// The json_name option of the descriptor's target.
+        /// </summary>
+        public string JsonName { get { return proto.JsonName == "" ? JsonFormatter.ToCamelCase(proto.Name) : proto.JsonName; } }
+
         internal FieldDescriptorProto Proto { get { return proto; } }
 
         /// <summary>
diff --git a/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs
index f5798d1e..f5a835e5 100644
--- a/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs
@@ -102,8 +102,8 @@ namespace Google.Protobuf.Reflection
             var map = new Dictionary<string, FieldDescriptor>();
             foreach (var field in fields)
             {
-                map[JsonFormatter.ToCamelCase(field.Name)] = field;
                 map[field.Name] = field;
+                map[field.JsonName] = field;
             }
             return new ReadOnlyDictionary<string, FieldDescriptor>(map);
         }