diff --git a/tests/tests.py b/tests/tests.py
index a305416..7255bc1 100755
--- a/tests/tests.py
+++ b/tests/tests.py
@@ -95,6 +95,21 @@ class F(Form):
         assert not form.validate()
         self.assertEqual(form.a.errors, ['Not a valid choice'])
 
+        form = F(a=sess.query(self.Test).filter_by(name='banana').first())
+        another_sess = self.Session()
+        form.a.query = another_sess.query(self.Test)
+        #this is the problem. not same pointer.
+        self.assertEqual(form.a(), [('1', 'apple', False), ('2', 'banana', False)])
+
+        #So, use coerce and get_pk for test
+        class F2(Form):
+            a = QuerySelectField(get_label='name', widget=LazySelect(), get_pk=lambda x: x.id, coerce=int)
+        form = F2(a=sess.query(self.Test).filter_by(name='banana').first())
+        another_sess = self.Session()
+        form.a.query = another_sess.query(self.Test)
+        self.assertEqual(form.a(), [('1', 'apple', False), ('2', 'banana', True)])
+
+
     def test_with_query_factory(self):
         sess = self.Session()
         self._fill(sess)
diff --git a/wtforms_sqlalchemy/fields.py b/wtforms_sqlalchemy/fields.py
index 286dada..df3c8be 100644
--- a/wtforms_sqlalchemy/fields.py
+++ b/wtforms_sqlalchemy/fields.py
@@ -51,14 +51,19 @@ class QuerySelectField(SelectFieldBase):
     top of the list. Selecting this choice will result in the `data` property
     being `None`. The label for this blank choice can be set by specifying the
     `blank_text` parameter.
+
+    If `coerce` and `get_pk` callables are specified, these two callables are
+    used for equality test. `coerce` should get pk and return value casted that
+    same type returned by `get_pk`. And selected is True when test passed.
     """
     widget = widgets.Select()
 
     def __init__(self, label=None, validators=None, query_factory=None,
                  get_pk=None, get_label=None, allow_blank=False,
-                 blank_text='', **kwargs):
+                 blank_text='', coerce=None, **kwargs):
         super(QuerySelectField, self).__init__(label, validators, **kwargs)
         self.query_factory = query_factory
+        self.coerce = coerce
 
         if get_pk is None:
             if not has_identity_key:
@@ -105,7 +110,9 @@ def iter_choices(self):
             yield ('__None', self.blank_text, self.data is None)
 
         for pk, obj in self._get_object_list():
-            yield (pk, self.get_label(obj), obj == self.data)
+            yield (pk, self.get_label(obj), obj == self.data or
+                   (self.coerce is not None  and self.get_pk is not None
+                    and self.coerce(pk) == self.get_pk(self.data)))
 
     def process_formdata(self, valuelist):
         if valuelist: