diff --git a/lib/application.js b/lib/application.js
index b9facad0..7a3abef5 100644
--- a/lib/application.js
+++ b/lib/application.js
@@ -390,13 +390,15 @@ function configureModel(ModelCtor, config, app) {
 
   var dataSource = config.dataSource;
 
-  if(typeof dataSource === 'string') {
-    dataSource = app.dataSources[dataSource];
-  }
+  if(dataSource) {
+    if(typeof dataSource === 'string') {
+      dataSource = app.dataSources[dataSource];
+    }
 
-  assert(dataSource instanceof DataSource,
-      ModelCtor.modelName + ' is referencing a dataSource that does not exist: "' +
-        config.dataSource +'"');
+    assert(dataSource instanceof DataSource,
+        ModelCtor.modelName + ' is referencing a dataSource that does not exist: "' +
+          config.dataSource +'"');
+  }
 
   config = extend({}, config);
   config.dataSource = dataSource;
diff --git a/lib/registry.js b/lib/registry.js
index 3cad9469..f7a03a1f 100644
--- a/lib/registry.js
+++ b/lib/registry.js
@@ -10,6 +10,7 @@
 var assert = require('assert');
 var extend = require('util')._extend;
 var juggler = require('loopback-datasource-juggler');
+var debug = require('debug')('loopback:registry');
 var DataSource = juggler.DataSource;
 var ModelBuilder = juggler.ModelBuilder;
 
@@ -171,6 +172,18 @@ registry.configureModel = function(ModelCtor, config) {
         'Cannot configure ' + ModelCtor.modelName +
         ': config.dataSource must be an instance of DataSource');
     ModelCtor.attachTo(config.dataSource);
+    debug('Attached model `%s` to dataSource `%s`',
+      ModelCtor.definition.name, config.dataSource.name);
+  } else if (config.dataSource === null) {
+    debug('Model `%s` is not attached to any DataSource by configuration.',
+      ModelCtor.definition.name);
+  } else {
+    debug('Model `%s` is not attached to any DataSource, possibly by a mistake.',
+      ModelCtor.definition.name);
+    console.warn(
+      'The configuration of `%s` is missing `dataSource` property.\n' +
+      'Use `null` or `false` to mark models not attached to any data source.',
+      ModelCtor.definition.name);
   }
 };
 
diff --git a/test/app.test.js b/test/app.test.js
index 2832a7b3..6d5b2937 100644
--- a/test/app.test.js
+++ b/test/app.test.js
@@ -69,6 +69,15 @@ describe('app', function() {
         request(app).get('/colors').expect(200, done);
       });
     });
+
+    it('accepts null dataSource', function() {
+      app.model('MyTestModel', { dataSource: null });
+    });
+
+    it('should not require dataSource', function() {
+      app.model('MyTestModel', {});
+    });
+
   });
 
   describe('app.model(name, config)', function () {
diff --git a/test/loopback.test.js b/test/loopback.test.js
index 17f9bc5b..6529d69c 100644
--- a/test/loopback.test.js
+++ b/test/loopback.test.js
@@ -185,6 +185,7 @@ describe('loopback', function() {
       var model = loopback.Model.extend(uniqueModelName);
 
       loopback.configureModel(model, {
+        dataSource: null,
         relations: {
           owner: {
             type: 'belongsTo',
@@ -207,6 +208,7 @@ describe('loopback', function() {
       });
 
       loopback.configureModel(model, {
+        dataSource: null,
         relations: {
           owner: {
             model: 'Application'