diff --git a/resend/contacts/_contacts.py b/resend/contacts/_contacts.py
index b35b643..3650a6c 100644
--- a/resend/contacts/_contacts.py
+++ b/resend/contacts/_contacts.py
@@ -250,29 +250,34 @@ def update(cls, params: UpdateParams) -> UpdateContactResponse:
 
     @classmethod
     def list(
-        cls, audience_id: Optional[str] = None, params: Optional[ListParams] = None
+        cls,
+        audience_id: Optional[str] = None,
+        params: Optional[ListParams] = None,
+        segment_id: Optional[str] = None,
     ) -> ListResponse:
         """
         List all contacts.
-        Can list either global contacts or audience-specific contacts.
+        Can list global contacts, audience-specific contacts, or segment contacts.
         see more: https://resend.com/docs/api-reference/contacts/list-contacts
 
         Args:
-            audience_id (Optional[str]): The audience ID. If not provided, lists all global contacts.
+            audience_id (Optional[str]): Deprecated. Use segment_id instead.
             params (Optional[ListParams]): Optional pagination parameters
                 - limit: Number of contacts to retrieve (max 100, min 1).
                   If not provided, all contacts will be returned without pagination.
                 - after: ID after which to retrieve more contacts
                 - before: ID before which to retrieve more contacts
+            segment_id (Optional[str]): The segment ID. When provided, lists contacts
+                in the segment via GET /segments/{segment_id}/contacts.
 
         Returns:
             ListResponse: A list of contact objects
         """
-        if audience_id:
-            # Audience-specific contacts
+        if segment_id:
+            base_path = f"/segments/{segment_id}/contacts"
+        elif audience_id:
             base_path = f"/audiences/{audience_id}/contacts"
         else:
-            # Global contacts
             base_path = "/contacts"
 
         query_params = cast(Dict[Any, Any], params) if params else None
@@ -419,21 +424,28 @@ async def update_async(cls, params: UpdateParams) -> UpdateContactResponse:
 
     @classmethod
     async def list_async(
-        cls, audience_id: Optional[str] = None, params: Optional[ListParams] = None
+        cls,
+        audience_id: Optional[str] = None,
+        params: Optional[ListParams] = None,
+        segment_id: Optional[str] = None,
     ) -> ListResponse:
         """
         List all contacts (async).
-        Can list either global contacts or audience-specific contacts.
+        Can list global contacts, audience-specific contacts, or segment contacts.
         see more: https://resend.com/docs/api-reference/contacts/list-contacts
 
         Args:
-            audience_id (Optional[str]): The audience ID. If not provided, lists all global contacts.
+            audience_id (Optional[str]): Deprecated. Use segment_id instead.
             params (Optional[ListParams]): Optional pagination parameters
+            segment_id (Optional[str]): The segment ID. When provided, lists contacts
+                in the segment via GET /segments/{segment_id}/contacts.
 
         Returns:
             ListResponse: A list of contact objects
         """
-        if audience_id:
+        if segment_id:
+            base_path = f"/segments/{segment_id}/contacts"
+        elif audience_id:
             base_path = f"/audiences/{audience_id}/contacts"
         else:
             base_path = "/contacts"
diff --git a/tests/contacts_async_test.py b/tests/contacts_async_test.py
index 2e73cf5..c24f758 100644
--- a/tests/contacts_async_test.py
+++ b/tests/contacts_async_test.py
@@ -248,3 +248,38 @@ async def test_should_list_contacts_async_raise_exception_when_no_content(
             _ = await resend.Contacts.list_async(
                 audience_id="48c269ed-9873-4d60-bdd9-cd7e6fc0b9b8"
             )
+
+    async def test_contacts_list_async_by_segment_id(self) -> None:
+        self.set_mock_json(
+            {
+                "object": "list",
+                "has_more": False,
+                "data": [
+                    {
+                        "id": "e169aa45-1ecf-4183-9955-b1499d5701d3",
+                        "email": "steve.wozniak@gmail.com",
+                        "first_name": "Steve",
+                        "last_name": "Wozniak",
+                        "created_at": "2023-10-06T23:47:56.678Z",
+                        "unsubscribed": False,
+                    }
+                ],
+            }
+        )
+
+        contacts: resend.Contacts.ListResponse = await resend.Contacts.list_async(
+            segment_id="78261eea-8f8b-4381-83c6-79fa7120f1cf"
+        )
+        assert contacts["object"] == "list"
+        assert contacts["has_more"] is False
+        assert contacts["data"][0]["id"] == "e169aa45-1ecf-4183-9955-b1499d5701d3"
+        assert contacts["data"][0]["email"] == "steve.wozniak@gmail.com"
+
+    async def test_should_list_contacts_async_by_segment_raise_exception_when_no_content(
+        self,
+    ) -> None:
+        self.set_mock_json(None)
+        with pytest.raises(NoContentError):
+            _ = await resend.Contacts.list_async(
+                segment_id="78261eea-8f8b-4381-83c6-79fa7120f1cf"
+            )
diff --git a/tests/contacts_test.py b/tests/contacts_test.py
index 6441df2..c0f965c 100644
--- a/tests/contacts_test.py
+++ b/tests/contacts_test.py
@@ -387,6 +387,65 @@ def test_contacts_list_global(self) -> None:
         assert contacts["data"][0]["id"] == "global-1"
         assert contacts["data"][1]["id"] == "global-2"
 
+    def test_contacts_list_by_segment_id(self) -> None:
+        self.set_mock_json(
+            {
+                "object": "list",
+                "has_more": False,
+                "data": [
+                    {
+                        "id": "e169aa45-1ecf-4183-9955-b1499d5701d3",
+                        "email": "steve.wozniak@gmail.com",
+                        "first_name": "Steve",
+                        "last_name": "Wozniak",
+                        "created_at": "2023-10-06T23:47:56.678Z",
+                        "unsubscribed": False,
+                    }
+                ],
+            }
+        )
+
+        contacts: resend.Contacts.ListResponse = resend.Contacts.list(
+            segment_id="78261eea-8f8b-4381-83c6-79fa7120f1cf"
+        )
+        assert contacts["object"] == "list"
+        assert contacts["has_more"] is False
+        assert contacts["data"][0]["id"] == "e169aa45-1ecf-4183-9955-b1499d5701d3"
+        assert contacts["data"][0]["email"] == "steve.wozniak@gmail.com"
+
+    def test_contacts_list_by_segment_id_with_pagination(self) -> None:
+        self.set_mock_json(
+            {
+                "object": "list",
+                "has_more": True,
+                "data": [
+                    {
+                        "id": "contact-1",
+                        "email": "contact1@example.com",
+                        "first_name": "Contact",
+                        "last_name": "One",
+                        "created_at": "2023-10-06T23:47:56.678Z",
+                        "unsubscribed": False,
+                    }
+                ],
+            }
+        )
+
+        params: resend.Contacts.ListParams = {"limit": 10, "after": "previous-id"}
+        contacts: resend.Contacts.ListResponse = resend.Contacts.list(
+            segment_id="78261eea-8f8b-4381-83c6-79fa7120f1cf", params=params
+        )
+        assert contacts["object"] == "list"
+        assert contacts["has_more"] is True
+        assert len(contacts["data"]) == 1
+
+    def test_should_list_contacts_by_segment_raise_exception_when_no_content(
+        self,
+    ) -> None:
+        self.set_mock_json(None)
+        with self.assertRaises(NoContentError):
+            _ = resend.Contacts.list(segment_id="78261eea-8f8b-4381-83c6-79fa7120f1cf")
+
     def test_contacts_remove_global_by_id(self) -> None:
         self.set_mock_json(
             {