diff --git a/azure_functions_worker/loader.py b/azure_functions_worker/loader.py
index 36787e65..a5ec98f3 100644
--- a/azure_functions_worker/loader.py
+++ b/azure_functions_worker/loader.py
@@ -143,18 +143,19 @@ def index_function_app(function_path: str):
     module_name = pathlib.Path(function_path).stem
     imported_module = importlib.import_module(module_name)
 
-    from azure.functions import FunctionApp
-    app: Optional[FunctionApp] = None
+    from azure.functions import FunctionRegister
+    app: Optional[FunctionRegister] = None
     for i in imported_module.__dir__():
-        if isinstance(getattr(imported_module, i, None), FunctionApp):
+        if isinstance(getattr(imported_module, i, None), FunctionRegister):
             if not app:
                 app = getattr(imported_module, i, None)
             else:
                 raise ValueError(
-                    "Multiple instances of FunctionApp are defined")
+                    f"More than one {app.__class__.__name__} or other top "
+                    f"level function app instances are defined.")
 
     if not app:
-        raise ValueError("Could not find instance of FunctionApp in "
+        raise ValueError("Could not find top level function app instances in "
                          f"{SCRIPT_FILE_NAME}.")
 
     return app.get_functions()
diff --git a/setup.py b/setup.py
index ab16cd39..0ffe06ec 100644
--- a/setup.py
+++ b/setup.py
@@ -105,7 +105,7 @@ INSTALL_REQUIRES = [
     "grpcio~=1.43.0",
     "grpcio-tools~=1.43.0",
     "protobuf~=3.19.3",
-    'azure-functions==1.11.3b2',
+    "azure-functions==1.11.3b2",
     "python-dateutil~=2.8.2"
 ]
 
diff --git a/tests/endtoend/blueprint_functions/functions_in_blueprint_only/blueprint.py b/tests/endtoend/blueprint_functions/functions_in_blueprint_only/blueprint.py
new file mode 100644
index 00000000..78504939
--- /dev/null
+++ b/tests/endtoend/blueprint_functions/functions_in_blueprint_only/blueprint.py
@@ -0,0 +1,31 @@
+import logging
+
+import azure.functions as func
+
+bp = func.Blueprint()
+
+
+@bp.route(route="default_template")
+def default_template(req: func.HttpRequest) -> func.HttpResponse:
+    logging.info('Python HTTP trigger function processed a request.')
+
+    name = req.params.get('name')
+    if not name:
+        try:
+            req_body = req.get_json()
+        except ValueError:
+            pass
+        else:
+            name = req_body.get('name')
+
+    if name:
+        return func.HttpResponse(
+            f"Hello, {name}. This HTTP triggered function "
+            f"executed successfully.")
+    else:
+        return func.HttpResponse(
+            "This HTTP triggered function executed successfully. "
+            "Pass a name in the query string or in the request body for a"
+            " personalized response.",
+            status_code=200
+        )
diff --git a/tests/endtoend/blueprint_functions/functions_in_blueprint_only/function_app.py b/tests/endtoend/blueprint_functions/functions_in_blueprint_only/function_app.py
new file mode 100644
index 00000000..fb045265
--- /dev/null
+++ b/tests/endtoend/blueprint_functions/functions_in_blueprint_only/function_app.py
@@ -0,0 +1,6 @@
+import azure.functions as func
+from blueprint import bp
+
+app = func.FunctionApp()
+
+app.register_functions(bp)
diff --git a/tests/endtoend/blueprint_functions/functions_in_both_blueprint_functionapp/blueprint.py b/tests/endtoend/blueprint_functions/functions_in_both_blueprint_functionapp/blueprint.py
new file mode 100644
index 00000000..78504939
--- /dev/null
+++ b/tests/endtoend/blueprint_functions/functions_in_both_blueprint_functionapp/blueprint.py
@@ -0,0 +1,31 @@
+import logging
+
+import azure.functions as func
+
+bp = func.Blueprint()
+
+
+@bp.route(route="default_template")
+def default_template(req: func.HttpRequest) -> func.HttpResponse:
+    logging.info('Python HTTP trigger function processed a request.')
+
+    name = req.params.get('name')
+    if not name:
+        try:
+            req_body = req.get_json()
+        except ValueError:
+            pass
+        else:
+            name = req_body.get('name')
+
+    if name:
+        return func.HttpResponse(
+            f"Hello, {name}. This HTTP triggered function "
+            f"executed successfully.")
+    else:
+        return func.HttpResponse(
+            "This HTTP triggered function executed successfully. "
+            "Pass a name in the query string or in the request body for a"
+            " personalized response.",
+            status_code=200
+        )
diff --git a/tests/endtoend/blueprint_functions/functions_in_both_blueprint_functionapp/function_app.py b/tests/endtoend/blueprint_functions/functions_in_both_blueprint_functionapp/function_app.py
new file mode 100644
index 00000000..4347b0c7
--- /dev/null
+++ b/tests/endtoend/blueprint_functions/functions_in_both_blueprint_functionapp/function_app.py
@@ -0,0 +1,13 @@
+import azure.functions as func
+
+from blueprint import bp
+
+app = func.FunctionApp()
+
+app.register_blueprint(bp)
+
+
+@app.route(route="return_http")
+def return_http(req: func.HttpRequest):
+    return func.HttpResponse('<h1>Hello World™</h1>',
+                             mimetype='text/html')
diff --git a/tests/endtoend/blueprint_functions/multiple_function_registers/function_app.py b/tests/endtoend/blueprint_functions/multiple_function_registers/function_app.py
new file mode 100644
index 00000000..4277df8d
--- /dev/null
+++ b/tests/endtoend/blueprint_functions/multiple_function_registers/function_app.py
@@ -0,0 +1,12 @@
+import azure.functions as func
+
+app = func.FunctionApp()
+
+
+@app.route(route="return_http")
+def return_http(req: func.HttpRequest):
+    return func.HttpResponse('<h1>Hello World™</h1>',
+                             mimetype='text/html')
+
+
+asgi_app = func.AsgiFunctionApp()
diff --git a/tests/endtoend/blueprint_functions/only_blueprint/function_app.py b/tests/endtoend/blueprint_functions/only_blueprint/function_app.py
new file mode 100644
index 00000000..78504939
--- /dev/null
+++ b/tests/endtoend/blueprint_functions/only_blueprint/function_app.py
@@ -0,0 +1,31 @@
+import logging
+
+import azure.functions as func
+
+bp = func.Blueprint()
+
+
+@bp.route(route="default_template")
+def default_template(req: func.HttpRequest) -> func.HttpResponse:
+    logging.info('Python HTTP trigger function processed a request.')
+
+    name = req.params.get('name')
+    if not name:
+        try:
+            req_body = req.get_json()
+        except ValueError:
+            pass
+        else:
+            name = req_body.get('name')
+
+    if name:
+        return func.HttpResponse(
+            f"Hello, {name}. This HTTP triggered function "
+            f"executed successfully.")
+    else:
+        return func.HttpResponse(
+            "This HTTP triggered function executed successfully. "
+            "Pass a name in the query string or in the request body for a"
+            " personalized response.",
+            status_code=200
+        )
diff --git a/tests/endtoend/test_blueprint_functions.py b/tests/endtoend/test_blueprint_functions.py
new file mode 100644
index 00000000..bb73fd91
--- /dev/null
+++ b/tests/endtoend/test_blueprint_functions.py
@@ -0,0 +1,59 @@
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License.
+
+from azure_functions_worker import testutils
+
+
+class TestFunctionInBluePrintOnly(testutils.WebHostTestCase):
+    @classmethod
+    def get_script_dir(cls):
+        return testutils.E2E_TESTS_FOLDER / 'blueprint_functions' / \
+            'functions_in_blueprint_only'
+
+    @testutils.retryable_test(3, 5)
+    def test_function_in_blueprint_only(self):
+        r = self.webhost.request('GET', 'default_template')
+        self.assertTrue(r.ok)
+
+
+class TestFunctionsInBothBlueprintAndFuncApp(testutils.WebHostTestCase):
+    @classmethod
+    def get_script_dir(cls):
+        return testutils.E2E_TESTS_FOLDER / 'blueprint_functions' / \
+            'functions_in_both_blueprint_functionapp'
+
+    @testutils.retryable_test(3, 5)
+    def test_functions_in_both_blueprint_functionapp(self):
+        r = self.webhost.request('GET', 'default_template')
+        self.assertTrue(r.ok)
+
+        r = self.webhost.request('GET', 'return_http')
+        self.assertTrue(r.ok)
+
+
+class TestMultipleFunctionRegisters(testutils.WebHostTestCase):
+    @classmethod
+    def get_script_dir(cls):
+        return testutils.E2E_TESTS_FOLDER / 'blueprint_functions' / \
+            'multiple_function_registers'
+
+    @testutils.retryable_test(3, 5)
+    def test_function_in_blueprint_only(self):
+        r = self.webhost.request('GET', 'return_http')
+        self.assertEqual(r.status_code, 404)
+
+
+class TestOnlyBlueprint(testutils.WebHostTestCase):
+    @classmethod
+    def get_script_dir(cls):
+        return testutils.E2E_TESTS_FOLDER / 'blueprint_functions' / \
+            'only_blueprint'
+
+    @testutils.retryable_test(3, 5)
+    def test_only_blueprint(self):
+        """Test if the default template of Http trigger in Python
+        Function app
+        will return OK
+        """
+        r = self.webhost.request('GET', 'default_template')
+        self.assertEqual(r.status_code, 404)
diff --git a/tests/endtoend/third_party_http_functions/stein/asgi_function/function_app.py b/tests/endtoend/third_party_http_functions/stein/asgi_function/function_app.py
index 0654b349..c5570be6 100644
--- a/tests/endtoend/third_party_http_functions/stein/asgi_function/function_app.py
+++ b/tests/endtoend/third_party_http_functions/stein/asgi_function/function_app.py
@@ -37,5 +37,5 @@ async def raise_http_exception():
     raise HTTPException(status_code=404, detail="Item not found")
 
 
-app = func.FunctionApp(asgi_app=fast_app,
-                       http_auth_level=func.AuthLevel.ANONYMOUS)
+app = func.AsgiFunctionApp(app=fast_app,
+                           http_auth_level=func.AuthLevel.ANONYMOUS)
diff --git a/tests/endtoend/third_party_http_functions/stein/wsgi_function/function_app.py b/tests/endtoend/third_party_http_functions/stein/wsgi_function/function_app.py
index 267fb85e..264a67a0 100644
--- a/tests/endtoend/third_party_http_functions/stein/wsgi_function/function_app.py
+++ b/tests/endtoend/third_party_http_functions/stein/wsgi_function/function_app.py
@@ -32,5 +32,5 @@ def raise_http_exception():
     return {"detail": "Item not found"}, 404
 
 
-app = func.FunctionApp(wsgi_app=flask_app.wsgi_app,
-                       http_auth_level=func.AuthLevel.ANONYMOUS)
+app = func.WsgiFunctionApp(app=flask_app.wsgi_app,
+                           http_auth_level=func.AuthLevel.ANONYMOUS)
diff --git a/tests/unittests/third_party_http_functions/stein/asgi_function/function_app.py b/tests/unittests/third_party_http_functions/stein/asgi_function/function_app.py
index 7ac32678..3248f25f 100644
--- a/tests/unittests/third_party_http_functions/stein/asgi_function/function_app.py
+++ b/tests/unittests/third_party_http_functions/stein/asgi_function/function_app.py
@@ -172,5 +172,5 @@ async def unhandled_unserializable_error():
     raise UnserializableException('foo')
 
 
-app = func.FunctionApp(asgi_app=fast_app,
-                       http_auth_level=func.AuthLevel.ANONYMOUS)
+app = func.AsgiFunctionApp(app=fast_app,
+                           http_auth_level=func.AuthLevel.ANONYMOUS)
diff --git a/tests/unittests/third_party_http_functions/stein/wsgi_function/function_app.py b/tests/unittests/third_party_http_functions/stein/wsgi_function/function_app.py
index dbd2c311..d08b3dc6 100644
--- a/tests/unittests/third_party_http_functions/stein/wsgi_function/function_app.py
+++ b/tests/unittests/third_party_http_functions/stein/wsgi_function/function_app.py
@@ -99,5 +99,5 @@ def unhandled_unserializable_error():
     raise UnserializableException('foo')
 
 
-app = func.FunctionApp(wsgi_app=flask_app.wsgi_app,
-                       http_auth_level=func.AuthLevel.ANONYMOUS)
+app = func.WsgiFunctionApp(app=flask_app.wsgi_app,
+                           http_auth_level=func.AuthLevel.ANONYMOUS)