diff --git a/mapping/JSONObjectMapping.cs b/mapping/JSONObjectMapping.cs
index ff94bfa..3d4c4ea 100644
--- a/mapping/JSONObjectMapping.cs
+++ b/mapping/JSONObjectMapping.cs
@@ -32,7 +32,9 @@ namespace ln.json.mapping
                 JSONMappingAttribute mappingAttribute = fieldInfo.GetCustomAttribute<JSONMappingAttribute>();
                 if ((mappingAttribute == null) || !mappingAttribute.Private)
                 {
-                    setters.Add(fieldInfo.Name, (object arg1, object arg2) => fieldInfo.SetValue(arg1, arg2));
+                    if (!fieldInfo.IsInitOnly)
+                        setters.Add(fieldInfo.Name, (object arg1, object arg2) => fieldInfo.SetValue(arg1, arg2));
+
                     getters.Add(fieldInfo.Name, (object arg) => fieldInfo.GetValue(arg));
                     types.Add(fieldInfo.Name, fieldInfo.FieldType);
                 }
@@ -42,7 +44,9 @@ namespace ln.json.mapping
                 JSONMappingAttribute mappingAttribute = propertyInfo.GetCustomAttribute<JSONMappingAttribute>();
                 if ((propertyInfo.GetIndexParameters().Length == 0) && ((mappingAttribute == null) || !mappingAttribute.Private))
                 {
-                    setters.Add(propertyInfo.Name, (object arg1, object arg2) => propertyInfo.SetValue(arg1, arg2));
+                    if (propertyInfo.CanWrite)
+                        setters.Add(propertyInfo.Name, (object arg1, object arg2) => propertyInfo.SetValue(arg1, arg2));
+
                     getters.Add(propertyInfo.Name, (object arg) => propertyInfo.GetValue(arg));
                     types.Add(propertyInfo.Name, propertyInfo.PropertyType);
                 }