diff --git a/tenable/io/scans.py b/tenable/io/scans.py
index 42b2a0fd6..6c5aff746 100644
--- a/tenable/io/scans.py
+++ b/tenable/io/scans.py
@@ -1175,7 +1175,7 @@ def launch(self,
 
     def list(self,
              folder_id: Optional[int] = None,
-             last_modified: Optional[int] = None
+             last_modified: Optional[datetime] = None
              ) -> List[Dict]:
         '''
         Retrieve the list of configured scans.
@@ -1199,11 +1199,13 @@ def list(self,
         params = {}
         if folder_id:
             params['folder_id'] = folder_id
-        if last_modified:
+        if last_modified and isinstance(last_modified, datetime):
             # for the last_modified datetime attribute, we will want to convert
             # that into a timestamp integer before passing it to the API.
-            lm = int(time.mktime(last_modified).timetuple())
+            lm = int(time.mktime(last_modified.timetuple()))
             params['last_modification_date'] = lm
+        if last_modified and isinstance(last_modified, int):
+            params['last_modification_date'] = last_modified
 
         return self._get(params=params).scans
 
diff --git a/tests/io/test_scans.py b/tests/io/test_scans.py
index 80f7d5f27..53e9d35ce 100644
--- a/tests/io/test_scans.py
+++ b/tests/io/test_scans.py
@@ -4,10 +4,14 @@
 import uuid
 import time
 import os
+import datetime
 import responses
 from io import BytesIO
 from sys import stdout
 import pytest
+import responses
+from tenable.io import TenableIO
+from responses.matchers import query_param_matcher
 from tenable.reports.nessusv2 import NessusReportv2
 from tenable.errors import UnexpectedValueError, NotFoundError, BadRequestError
 from tests.checker import check, single
@@ -1955,3 +1959,19 @@ def test_scan_create_scan_document_credentials_compliance_plugins(api):
                                                                                        'auth_method': 'Password'}]}},
                                                  'compliance': {'test': 'testvalue'},
                                                  'plugins': {12122: 13, 12050: 13}})
+
+
+@responses.activate
+def test_list_api():
+    dt = datetime.datetime(2024, 1, 1)
+    dt_int = int(time.mktime(dt.timetuple()))
+    responses.get(
+        'https://nourl/scans',
+        json={'scans': []},
+        match=[
+            query_param_matcher({'last_modification_date': dt_int,'folder_id': 1})
+        ]
+    )
+    tvm = TenableIO(url='https://nourl', access_key='something', secret_key='something')
+    assert tvm.scans.list(folder_id=1, last_modified=dt) == []
+    assert tvm.scans.list(folder_id=1, last_modified=dt_int) == []