diff --git a/pony/orm/core.py b/pony/orm/core.py
index b514277b2..e89f94cd7 100644
--- a/pony/orm/core.py
+++ b/pony/orm/core.py
@@ -298,11 +298,11 @@ def copy(self):
         result.entities_to_prefetch = self.entities_to_prefetch.copy()
         return result
     def __enter__(self):
-        assert local.prefetch_context is None
-        local.prefetch_context = self
+        local.prefetch_context_stack.append(self)
     def __exit__(self, exc_type, exc_val, exc_tb):
-        assert local.prefetch_context is self
-        local.prefetch_context = None
+        stack = local.prefetch_context_stack
+        assert stack and stack[-1] is self
+        stack.pop()
     def get_frozen_attrs_to_prefetch(self, entity):
         attrs_to_prefetch = self.attrs_to_prefetch_dict.get(entity, ())
         if type(attrs_to_prefetch) is set:
@@ -329,11 +329,16 @@ def __init__(local):
         local.db2cache = {}
         local.db_context_counter = 0
         local.db_session = None
-        local.prefetch_context = None
+        local.prefetch_context_stack = []
         local.current_user = None
         local.perms_context = None
         local.user_groups_cache = {}
         local.user_roles_cache = defaultdict(dict)
+    @property
+    def prefetch_context(local):
+        if local.prefetch_context_stack:
+            return local.prefetch_context_stack[-1]
+        return None
     def push_debug_state(local, debug, show_values):
         local.debug_stack.append((local.debug, local.show_values))
         if not suppress_debug_change:
diff --git a/pony/orm/tests/test_hooks.py b/pony/orm/tests/test_hooks.py
index af3c2002f..33f55e675 100644
--- a/pony/orm/tests/test_hooks.py
+++ b/pony/orm/tests/test_hooks.py
@@ -57,6 +57,11 @@ def set_hooks_to_do_nothing():
 set_hooks_to_do_nothing()
 
 
+def flush_for(*objects):
+    for obj in objects:
+        obj.flush()
+
+
 class TestHooks(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
@@ -79,7 +84,7 @@ def tearDown(self):
         pass
 
     @db_session
-    def test_1(self):
+    def test_1a(self):
         p4 = Person(id=4, name='Bob', age=16)
         p5 = Person(id=5, name='Lucy', age=23)
         self.assertEqual(logged_events, [])
@@ -87,7 +92,15 @@ def test_1(self):
         self.assertEqual(logged_events, ['BI_Bob', 'BI_Lucy', 'AI_Bob', 'AI_Lucy'])
 
     @db_session
-    def test_2(self):
+    def test_1b(self):
+        p4 = Person(id=4, name='Bob', age=16)
+        p5 = Person(id=5, name='Lucy', age=23)
+        self.assertEqual(logged_events, [])
+        flush_for(p4, p5)
+        self.assertEqual(logged_events, ['BI_Bob', 'AI_Bob', 'BI_Lucy', 'AI_Lucy'])
+
+    @db_session
+    def test_2a(self):
         p4 = Person(id=4, name='Bob', age=16)
         p1 = Person[1]  # auto-flush here
         p2 = Person[2]
@@ -98,50 +111,7 @@ def test_2(self):
         self.assertEqual(logged_events, ['BI_Bob', 'AI_Bob', 'BU_Mary', 'BI_Lucy', 'AU_Mary', 'AI_Lucy'])
 
     @db_session
-    def test_3(self):
-        global do_before_insert
-        def do_before_insert(person):
-            some_person = Person.select().first()  # should not cause infinite recursion
-        p4 = Person(id=4, name='Bob', age=16)
-        db.flush()
-
-
-def flush_for(*objects):
-    for obj in objects:
-        obj.flush()
-
-
-class ObjectFlushTest(unittest.TestCase):
-    @classmethod
-    def setUpClass(cls):
-        setup_database(db)
-
-    @classmethod
-    def tearDownClass(cls):
-        teardown_database(db)
-
-    def setUp(self):
-        set_hooks_to_do_nothing()
-        with db_session:
-            db.execute('delete from Person')
-            p1 = Person(id=1, name='John', age=22)
-            p2 = Person(id=2, name='Mary', age=18)
-            p3 = Person(id=3, name='Mike', age=25)
-        logged_events[:] = []
-
-    def tearDown(self):
-        pass
-
-    @db_session
-    def test_1(self):
-        p4 = Person(id=4, name='Bob', age=16)
-        p5 = Person(id=5, name='Lucy', age=23)
-        self.assertEqual(logged_events, [])
-        flush_for(p4, p5)
-        self.assertEqual(logged_events, ['BI_Bob', 'AI_Bob', 'BI_Lucy', 'AI_Lucy'])
-
-    @db_session
-    def test_2(self):
+    def test_2b(self):
         p4 = Person(id=4, name='Bob', age=16)
         p1 = Person[1]  # auto-flush here
         p2 = Person[2]
@@ -157,7 +127,15 @@ def test_3(self):
         def do_before_insert(person):
             some_person = Person.select().first()  # should not cause infinite recursion
         p4 = Person(id=4, name='Bob', age=16)
-        p4.flush()
+        db.flush()
+
+    @db_session
+    def test_4(self):
+        global do_before_insert
+        def do_before_insert(person):
+            some_person = Person.select().first()  # creates nested prefetch_context
+        p4 = Person(id=4, name='Bob', age=16)
+        Person.select().first()
 
 
 if __name__ == '__main__':