diff --git a/tableauserverclient/datetime_helpers.py b/tableauserverclient/datetime_helpers.py
index 95041f8e1..2b1df202c 100644
--- a/tableauserverclient/datetime_helpers.py
+++ b/tableauserverclient/datetime_helpers.py
@@ -28,8 +28,14 @@ def parse_datetime(date):
     if date is None:
         return None
 
-    return datetime.datetime.strptime(date, TABLEAU_DATE_FORMAT).replace(tzinfo=utc)
+    try:
+        return datetime.datetime.strptime(date, TABLEAU_DATE_FORMAT).replace(tzinfo=utc)
+    except ValueError:
+        return None
 
 
 def format_datetime(date):
+    if date is None:
+        return None
+
     return date.astimezone(tz=utc).strftime(TABLEAU_DATE_FORMAT)
diff --git a/test/assets/workbook_get_invalid_date.xml b/test/assets/workbook_get_invalid_date.xml
new file mode 100644
index 000000000..c580f9eb6
--- /dev/null
+++ b/test/assets/workbook_get_invalid_date.xml
@@ -0,0 +1,11 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<tsResponse xmlns="http://tableau.com/api" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://tableau.com/api http://tableau.com/api/ts-api-2.3.xsd">
+    <pagination pageNumber="1" pageSize="100" totalAvailable="2" />
+    <workbooks>
+        <workbook id="6d13b0ca-043d-4d42-8c9d-3f3313ea3a00" name="Superstore" contentUrl="Superstore" showTabs="false" size="1" createdAt="2016-06-31T20:34:04Z" updatedAt="2016-08-04T17:56:41Z">
+            <project id="ee8c6e70-43b6-11e6-af4f-f7b0d8e20760" name="default" />
+            <owner id="5de011f8-5aa9-4d5b-b991-f462c8dd6bb7" />
+            <tags />
+        </workbook>
+    </workbooks>
+</tsResponse>
\ No newline at end of file
diff --git a/test/test_workbook.py b/test/test_workbook.py
index 1a68f3437..58880b7b1 100644
--- a/test/test_workbook.py
+++ b/test/test_workbook.py
@@ -20,6 +20,7 @@
 ADD_TAGS_XML = os.path.join(TEST_ASSET_DIR, 'workbook_add_tags.xml')
 GET_BY_ID_XML = os.path.join(TEST_ASSET_DIR, 'workbook_get_by_id.xml')
 GET_EMPTY_XML = os.path.join(TEST_ASSET_DIR, 'workbook_get_empty.xml')
+GET_INVALID_DATE_XML = os.path.join(TEST_ASSET_DIR, 'workbook_get_invalid_date.xml')
 GET_XML = os.path.join(TEST_ASSET_DIR, 'workbook_get.xml')
 POPULATE_CONNECTIONS_XML = os.path.join(TEST_ASSET_DIR, 'workbook_populate_connections.xml')
 POPULATE_PDF = os.path.join(TEST_ASSET_DIR, 'populate_pdf.pdf')
@@ -79,6 +80,15 @@ def test_get(self):
         self.assertEqual('5de011f8-5aa9-4d5b-b991-f462c8dd6bb7', all_workbooks[1].owner_id)
         self.assertEqual(set(['Safari', 'Sample']), all_workbooks[1].tags)
 
+    def test_get_ignore_invalid_date(self):
+        with open(GET_INVALID_DATE_XML, 'rb') as f:
+            response_xml = f.read().decode('utf-8')
+        with requests_mock.mock() as m:
+            m.get(self.baseurl, text=response_xml)
+            all_workbooks, pagination_item = self.server.workbooks.get()
+        self.assertEqual(None, format_datetime(all_workbooks[0].created_at))
+        self.assertEqual('2016-08-04T17:56:41Z', format_datetime(all_workbooks[0].updated_at))
+
     def test_get_before_signin(self):
         self.server._auth_token = None
         self.assertRaises(TSC.NotSignedInError, self.server.workbooks.get)