diff --git a/tests/data/test_defaults.py b/tests/data/test_defaults.py
index 9dad345..8d5fe85 100644
--- a/tests/data/test_defaults.py
+++ b/tests/data/test_defaults.py
@@ -16,6 +16,11 @@
     "timezone": "Europe/Moscow",
 }
 
+DEFAULT_DURATION_RESPONSE = {
+    "amount": 60,
+    "unit": "minute",
+}
+
 DEFAULT_TASK_RESPONSE = {
     "id": "1234",
     "assigner_id": "2971358",
@@ -35,6 +40,7 @@
     "created_at": "2019-01-02T21:00:30.00000Z",
     "url": "https://todoist.com/showTask?id=2995104339",
     "due": DEFAULT_DUE_RESPONSE,
+    "duration": DEFAULT_DURATION_RESPONSE,
 }
 
 DEFAULT_TASK_RESPONSE_2 = dict(DEFAULT_TASK_RESPONSE)
diff --git a/tests/test_models.py b/tests/test_models.py
index d6ad6b0..e5c6690 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -8,6 +8,7 @@
     DEFAULT_COMMENT_RESPONSE,
     DEFAULT_COMPLETED_ITEMS_RESPONSE,
     DEFAULT_DUE_RESPONSE,
+    DEFAULT_DURATION_RESPONSE,
     DEFAULT_ITEM_COMPLETED_INFO_RESPONSE,
     DEFAULT_ITEM_RESPONSE,
     DEFAULT_LABEL_RESPONSE,
@@ -22,6 +23,7 @@
     Comment,
     CompletedItems,
     Due,
+    Duration,
     Item,
     ItemCompletedInfo,
     Label,
@@ -80,6 +82,16 @@ def test_due_from_dict():
     assert due.timezone == sample_data["timezone"]
 
 
+def test_duration_from_dict():
+    sample_data = dict(DEFAULT_DURATION_RESPONSE)
+    sample_data.update(unexpected_data)
+
+    duration = Duration.from_dict(sample_data)
+
+    assert duration.amount == sample_data["amount"]
+    assert duration.unit == sample_data["unit"]
+
+
 def test_task_from_dict():
     sample_data = dict(DEFAULT_TASK_RESPONSE)
     sample_data.update(unexpected_data)
@@ -102,6 +114,34 @@ def test_task_from_dict():
     assert task.labels == sample_data["labels"]
     assert task.order == sample_data["order"]
     assert task.parent_id == sample_data["parent_id"]
+    assert task.duration == Duration.from_dict(sample_data["duration"])
+
+
+def test_task_to_dict():
+    sample_data = dict(DEFAULT_TASK_RESPONSE)
+    sample_data.update(unexpected_data)
+
+    task = Task.from_dict(sample_data).to_dict()
+
+    assert task["comment_count"] == sample_data["comment_count"]
+    assert task["is_completed"] == sample_data["is_completed"]
+    assert task["content"] == sample_data["content"]
+    assert task["created_at"] == sample_data["created_at"]
+    assert task["creator_id"] == sample_data["creator_id"]
+    assert task["id"] == sample_data["id"]
+    assert task["project_id"] == sample_data["project_id"]
+    assert task["section_id"] == sample_data["section_id"]
+    assert task["priority"] == sample_data["priority"]
+    assert task["url"] == sample_data["url"]
+    assert task["assignee_id"] == sample_data["assignee_id"]
+    assert task["assigner_id"] == sample_data["assigner_id"]
+    for key in task["due"]:
+        assert task["due"][key] == sample_data["due"][key]
+    assert task["labels"] == sample_data["labels"]
+    assert task["order"] == sample_data["order"]
+    assert task["parent_id"] == sample_data["parent_id"]
+    for key in task["duration"]:
+        assert task["duration"][key] == sample_data["duration"][key]
 
 
 def test_collaborator_from_dict():
diff --git a/todoist_api_python/models.py b/todoist_api_python/models.py
index 37e4729..ed1c9fa 100644
--- a/todoist_api_python/models.py
+++ b/todoist_api_python/models.py
@@ -163,15 +163,19 @@ def from_dict(cls, obj):
             project_id=obj["project_id"],
             section_id=obj["section_id"],
             url=obj["url"],
-            duration=duration
+            duration=duration,
         )
 
     def to_dict(self):
         due: dict | None = None
+        duration: dict | None = None
 
         if self.due:
             due = self.due.to_dict()
 
+        if self.duration:
+            duration = self.duration.to_dict()
+
         return {
             "assignee_id": self.assignee_id,
             "assigner_id": self.assigner_id,
@@ -191,7 +195,7 @@ def to_dict(self):
             "section_id": self.section_id,
             "sync_id": self.sync_id,
             "url": self.url,
-            "duration": self.duration
+            "duration": duration,
         }
 
     @classmethod
@@ -438,7 +442,7 @@ def from_dict(cls, obj: dict[str, Any]) -> CompletedItems:
 
 
 @dataclass
-class Duration(object):
+class Duration:
     amount: int
     unit: str