diff --git a/src/LitJson/JsonMapper.cs b/src/LitJson/JsonMapper.cs
index 5a0a436..5cd9268 100644
--- a/src/LitJson/JsonMapper.cs
+++ b/src/LitJson/JsonMapper.cs
@@ -779,10 +779,13 @@ private static void WriteValue (object obj, JsonWriter writer,
                 return;
             }
 
-            if (obj is IDictionary) {
+            if (obj is IDictionary dictionary) {
                 writer.WriteObjectStart ();
-                foreach (DictionaryEntry entry in (IDictionary) obj) {
-                    writer.WritePropertyName ((string) entry.Key);
+                foreach (DictionaryEntry entry in dictionary) {
+                    var propertyName = entry.Key is string key ?
+                        key
+                        : Convert.ToString(entry.Key, CultureInfo.InvariantCulture);
+                    writer.WritePropertyName (propertyName);
                     WriteValue (entry.Value, writer, writer_is_private,
                                 depth + 1);
                 }
diff --git a/test/JsonMapperTest.cs b/test/JsonMapperTest.cs
index 17829a9..a980cfa 100644
--- a/test/JsonMapperTest.cs
+++ b/test/JsonMapperTest.cs
@@ -306,6 +306,22 @@ public void ExportEnumsTest ()
             Assert.AreEqual ("{\"FavouritePlanet\":1,\"Band\":9}", json);
         }
 
+        [Test]
+        public void ExportEnumDictionaryTest()
+        {
+            Dictionary<Planets, int> planets = new Dictionary<Planets, int>();
+            
+            planets.Add(Planets.Jupiter, 5);
+            planets.Add(Planets.Saturn, 6);
+            planets.Add(Planets.Uranus, 7);
+            planets.Add(Planets.Neptune, 8);
+            planets.Add(Planets.Pluto, 9);
+            
+            string json = JsonMapper.ToJson(planets);
+
+            Assert.AreEqual("{\"Jupiter\":5,\"Saturn\":6,\"Uranus\":7,\"Neptune\":8,\"Pluto\":9}", json);
+        }
+
         [Test]
         public void ExportObjectTest ()
         {