diff --git a/aiogram/api/types/chat_member.py b/aiogram/api/types/chat_member.py
index 593a86fb..967d35f6 100644
--- a/aiogram/api/types/chat_member.py
+++ b/aiogram/api/types/chat_member.py
@@ -3,8 +3,9 @@ from __future__ import annotations
 import datetime
 from typing import TYPE_CHECKING, Optional, Union
 
-from .base import TelegramObject
 from ...utils import helper
+from ...utils.helper import HelperMode, Item
+from .base import TelegramObject
 
 if TYPE_CHECKING:  # pragma: no cover
     from .user import User
@@ -73,18 +74,24 @@ class ChatMember(TelegramObject):
 
     @property
     def is_chat_member(self) -> bool:
-        return self.status not in {ChatMemberStatus.LEFT, ChatMemberStatus.KICKED}
+        return self.status in {
+            ChatMemberStatus.CREATOR,
+            ChatMemberStatus.MEMBER,
+            ChatMemberStatus.ADMINISTRATOR,
+            ChatMemberStatus.RESTRICTED,
+        }
 
 
 class ChatMemberStatus(helper.Helper):
     """
     Chat member status
     """
-    mode = helper.HelperMode.lowercase
 
-    CREATOR = helper.Item()  # creator
-    ADMINISTRATOR = helper.Item()  # administrator
-    MEMBER = helper.Item()  # member
-    RESTRICTED = helper.Item()  # restricted
-    LEFT = helper.Item()  # left
-    KICKED = helper.Item()  # kicked
+    mode = HelperMode.lowercase
+
+    CREATOR = Item()
+    ADMINISTRATOR = Item()
+    MEMBER = Item()
+    RESTRICTED = Item()
+    LEFT = Item()
+    KICKED = Item()
diff --git a/tests/test_api/test_types/test_chat_member.py b/tests/test_api/test_types/test_chat_member.py
index e5706e5e..6f08dc69 100644
--- a/tests/test_api/test_types/test_chat_member.py
+++ b/tests/test_api/test_types/test_chat_member.py
@@ -2,33 +2,39 @@ import pytest
 
 from aiogram.api.types import ChatMember, User
 
-user = User(id=42, is_bot=False, first_name="User", last_name=None)
-
 
 class TestChatMember:
+    def setup(self):
+        self.__user = User(id=42, is_bot=False, first_name="User", last_name=None)
+
     @pytest.mark.parametrize(
-        "status,result",
+        "status, expected_status",
         [
             ["administrator", True],
             ["creator", True],
-            ["member", False]
-        ]
+            ["member", False],
+            ["restricted", False],
+            ["kicked", False],
+            ["left", False],
+            ["durov", False],  # not a valid status value, method should return False
+        ],
     )
-    def test_is_chat_admin(self, status: str, result: bool):
-        chat_member = ChatMember(user=user, status=status)
-        assert chat_member.is_chat_admin == result
+    def test_is_chat_admin(self, status: str, expected_status: bool):
+        chat_member = ChatMember(user=self.__user, status=status)
+        assert chat_member.is_chat_admin == expected_status
 
     @pytest.mark.parametrize(
-        "status,result",
+        "status, expected_status",
         [
             ["administrator", True],
             ["creator", True],
             ["member", True],
             ["restricted", True],
             ["kicked", False],
-            ["left", False]
-        ]
+            ["left", False],
+            ["onotole", False],  # not a valid status value, method should return False
+        ],
     )
-    def test_is_chat_member(self, status: str, result: bool):
-        chat_member = ChatMember(user=user, status=status)
-        assert chat_member.is_chat_member == result
+    def test_is_chat_member(self, status: str, expected_status: bool):
+        chat_member = ChatMember(user=self.__user, status=status)
+        assert chat_member.is_chat_member == expected_status