diff --git a/LiteDB/Client/Mapper/BsonMapper.Deserialize.cs b/LiteDB/Client/Mapper/BsonMapper.Deserialize.cs
index d2e23943b..3b6c474dd 100644
--- a/LiteDB/Client/Mapper/BsonMapper.Deserialize.cs
+++ b/LiteDB/Client/Mapper/BsonMapper.Deserialize.cs
@@ -165,7 +165,7 @@ public object Deserialize(Type type, BsonValue value)
                 var doc = value.AsDocument;
 
                 // test if value is object and has _type
-                if (doc.TryGetValue("_type", out var typeField) && typeField.IsString)
+                if (doc.TryGetValue(BsonMapper.Global.TypeDescriptor, out var typeField) && typeField.IsString)
                 {
                     type = _typeNameBinder.GetType(typeField.AsString);
 
diff --git a/LiteDB/Client/Mapper/BsonMapper.Serialize.cs b/LiteDB/Client/Mapper/BsonMapper.Serialize.cs
index 1e013b16c..ffcafa3c1 100644
--- a/LiteDB/Client/Mapper/BsonMapper.Serialize.cs
+++ b/LiteDB/Client/Mapper/BsonMapper.Serialize.cs
@@ -185,7 +185,7 @@ private BsonDocument SerializeObject(Type type, object obj, int depth)
             // adding _type only where property Type is not same as object instance type
             if (type != t)
             {
-                doc["_type"] = new BsonValue(_typeNameBinder.GetName(t));
+                doc[BsonMapper.Global.TypeDescriptor] = new BsonValue(_typeNameBinder.GetName(t));
             }
 
             foreach (var member in entity.Members.Where(x => x.Getter != null))
@@ -194,6 +194,7 @@ private BsonDocument SerializeObject(Type type, object obj, int depth)
                 var value = member.Getter(obj);
 
                 if (value == null && this.SerializeNullValues == false && member.FieldName != "_id") continue;
+                // Console.WriteLine(member.FieldName + " " + member.DataType.Name);
 
                 // if member has a custom serialization, use it
                 if (member.Serialize != null)
diff --git a/LiteDB/Client/Mapper/BsonMapper.cs b/LiteDB/Client/Mapper/BsonMapper.cs
index 304902b58..ebfcb9dd9 100644
--- a/LiteDB/Client/Mapper/BsonMapper.cs
+++ b/LiteDB/Client/Mapper/BsonMapper.cs
@@ -94,6 +94,8 @@ public partial class BsonMapper
         /// </summary>
         public int MaxDepth { get; set; }
 
+        public string TypeDescriptor { get; set; }
+
         /// <summary>
         /// A custom callback to change MemberInfo behavior when converting to MemberMapper.
         /// Use mapper.ResolveMember(Type entity, MemberInfo property, MemberMapper documentMappedField)
@@ -119,6 +121,7 @@ public BsonMapper(Func<Type, object> customTypeInstantiator = null, ITypeNameBin
             this.ResolveCollectionName = (t) => Reflection.IsEnumerable(t) ? Reflection.GetListItemType(t).Name : t.Name;
             this.IncludeFields = false;
             this.MaxDepth = 20;
+            this.TypeDescriptor = "_type";
 
             _typeInstantiator = customTypeInstantiator ?? ((Type t) => null);
             _typeNameBinder = typeNameBinder ?? DefaultTypeNameBinder.Instance;
@@ -524,7 +527,7 @@ private static void RegisterDbRefItem(BsonMapper mapper, MemberMapper member, IT
                     doc["_id"] = idRef;
                     if (doc.ContainsKey("$type"))
                     {
-                        doc["_type"] = bson["$type"];
+                        doc[BsonMapper.Global.TypeDescriptor] = bson["$type"];
                     }
 
                     return m.Deserialize(entity.ForType, doc);
@@ -534,7 +537,7 @@ private static void RegisterDbRefItem(BsonMapper mapper, MemberMapper member, IT
                 {
                     return m.Deserialize(entity.ForType,
                         doc.ContainsKey("$type") ?
-                            new BsonDocument { ["_id"] = idRef, ["_type"] = bson["$type"] } :
+                            new BsonDocument { ["_id"] = idRef, [BsonMapper.Global.TypeDescriptor] = bson["$type"] } :
                             new BsonDocument { ["_id"] = idRef }); // if has $id, deserialize object using only _id object
                 }
 
@@ -609,7 +612,7 @@ private static void RegisterDbRefList(BsonMapper mapper, MemberMapper member, IT
                         item["_id"] = idRef;
                         if (item.AsDocument.ContainsKey("$type"))
                         {
-                            item["_type"] = item["$type"];
+                            item[BsonMapper.Global.TypeDescriptor] = item["$type"];
                         }
 
                         result.Add(item);
@@ -620,7 +623,7 @@ private static void RegisterDbRefList(BsonMapper mapper, MemberMapper member, IT
 
                         if (item.AsDocument.ContainsKey("$type"))
                         {
-                            bsonDocument["_type"] = item["$type"];
+                            bsonDocument[BsonMapper.Global.TypeDescriptor] = item["$type"];
                         }
 
                         result.Add(bsonDocument);