diff --git a/lib/mysql.js b/lib/mysql.js
index 135e448..28f0069 100644
--- a/lib/mysql.js
+++ b/lib/mysql.js
@@ -323,6 +323,9 @@ MySQL.prototype.toDatabase = function (prop, val, forCreate) {
   if (!prop) {
     return this.client.escape(val);
   }
+  if (prop.type === String) {
+    return this.client.escape(String(val));
+  }
   if (prop.type === Number) {
     if (isNaN(val)) {
       val = null;
@@ -345,16 +348,25 @@ MySQL.prototype.toDatabase = function (prop, val, forCreate) {
     return val ? 'Point(' + val.lat + ',' + val.lng + ')' : 'NULL';
   }
   if (prop.type === Object) {
-    return this.client.escape(val);
+    return this._serializeObject(val);
   }
   if (typeof prop.type === 'function') {
-    if (prop.type.modelName) {
-      // For embedded models
-      return this.client.escape(JSON.stringify(val));
-    }
-    return this.client.escape(prop.type(val));
+    return this._serializeObject(val);
   }
-  return this.client.escape(val.toString());
+  return this._serializeObject(val);
+};
+
+MySQL.prototype._serializeObject = function(obj) {
+  var val;
+  if (obj && typeof obj.toJSON === 'function') {
+    obj = obj.toJSON();
+  }
+  if (typeof obj !== 'string') {
+    val = JSON.stringify(obj);
+  } else {
+    val = obj;
+  }
+  return this.client.escape(val);
 };
 
 /*!
@@ -381,6 +393,12 @@ MySQL.prototype.fromDatabase = function (model, data) {
     }
     if (props[p]) {
       switch (props[p].type.name) {
+        case 'Number':
+          val = Number(val);
+          break;
+        case 'String':
+          val = String(val);
+          break;
         case 'Date':
           val = new Date(val.toString().replace(/GMT.*$/, 'GMT'));
           break;
@@ -394,6 +412,17 @@ MySQL.prototype.fromDatabase = function (model, data) {
             lng: val.y
           };
           break;
+        case 'List':
+        case 'Array':
+        case 'Object':
+        case 'JSON':
+          break;
+        default:
+          if (!Array.isArray(props[p].type) && !props[p].type.modelName) {
+            // Do not convert array and model types
+            val = props[p].type(val);
+          }
+          break;
       }
     }
     json[p] = val;
diff --git a/test/mysql.test.js b/test/mysql.test.js
index c4c5a96..2f533e1 100644
--- a/test/mysql.test.js
+++ b/test/mysql.test.js
@@ -2,6 +2,19 @@ var should = require('./init.js');
 
 var Post, PostWithStringId, PostWithUniqueTitle, db;
 
+// Mock up mongodb ObjectID
+function ObjectID(id) {
+  if (!(this instanceof ObjectID)) {
+    return new ObjectID(id);
+  }
+  this.id1 = id.substring(0, 2);
+  this.id2 = id.substring(2);
+}
+
+ObjectID.prototype.toJSON = function() {
+  return this.id1 + this.id2;
+};
+
 describe('mysql', function () {
 
   before(function (done) {
@@ -12,7 +25,8 @@ describe('mysql', function () {
       content: { type: String },
       comments: [String],
       history: Object,
-      stars: Number
+      stars: Number,
+      userId: ObjectID
     });
 
     PostWithStringId = db.define('PostWithStringId', {
@@ -44,11 +58,11 @@ describe('mysql', function () {
 
   it('should allow array or object', function (done) {
     Post.create({title: 'a', content: 'AAA', comments: ['1', '2'],
-      history: {a: 1, b: 'b'}}, function (err, post) {
+      history: {a: 1, b: 'b'}}, function(err, post) {
 
       should.not.exist(err);
 
-      Post.findById(post.id, function (err, p) {
+      Post.findById(post.id, function(err, p) {
         p.id.should.be.equal(post.id);
 
         p.content.should.be.equal(post.content);
@@ -59,7 +73,24 @@ describe('mysql', function () {
         done();
       });
     });
+  });
 
+  it('should allow ObjectID', function(done) {
+    var uid = new ObjectID('123');
+    Post.create({title: 'a', content: 'AAA', userId: uid},
+      function(err, post) {
+
+        should.not.exist(err);
+
+        Post.findById(post.id, function(err, p) {
+          p.id.should.be.equal(post.id);
+
+          p.content.should.be.equal(post.content);
+          p.title.should.be.equal('a');
+          p.userId.should.eql(uid);
+          done();
+        });
+      });
   });
 
   it('updateOrCreate should update the instance', function (done) {