diff --git a/src/flask_marshmallow/__init__.py b/src/flask_marshmallow/__init__.py
index a0f0f1c..a3afa4d 100755
--- a/src/flask_marshmallow/__init__.py
+++ b/src/flask_marshmallow/__init__.py
@@ -111,7 +111,7 @@ def init_app(self, app):
 
         # If using Flask-SQLAlchemy, attach db.session to SQLAlchemySchema
         if has_sqla and "sqlalchemy" in app.extensions:
-            db = app.extensions["sqlalchemy"].db
+            db = app.extensions["sqlalchemy"]
             if self.SQLAlchemySchema:
                 self.SQLAlchemySchema.OPTIONS_CLASS.session = db.session
             if self.SQLAlchemyAutoSchema: