diff --git a/document-parser/services/analysis_service.py b/document-parser/services/analysis_service.py
index 36c2f5a..f003285 100644
--- a/document-parser/services/analysis_service.py
+++ b/document-parser/services/analysis_service.py
@@ -53,6 +53,7 @@ class AnalysisService:
         self._chunker = chunker
         self._conversion_timeout = conversion_timeout
         self._semaphore = asyncio.Semaphore(max_concurrent)
+        self._running_tasks: dict[str, asyncio.Task] = {}
 
     async def create(
         self,
@@ -79,7 +80,8 @@ class AnalysisService:
                 chunking_options,
             )
         )
-        task.add_done_callback(functools.partial(_on_task_done, job_id=job.id))
+        self._running_tasks[job.id] = task
+        task.add_done_callback(functools.partial(self._on_task_done, job_id=job.id))
 
         return job
 
@@ -92,7 +94,11 @@ class AnalysisService:
         return await analysis_repo.find_by_id(job_id)
 
     async def delete(self, job_id: str) -> bool:
-        """Delete an analysis job. Returns True if it existed."""
+        """Delete an analysis job, cancelling any running task. Returns True if it existed."""
+        task = self._running_tasks.pop(job_id, None)
+        if task and not task.done():
+            task.cancel()
+            logger.info("Cancelled running task for job %s", job_id)
         return await analysis_repo.delete(job_id)
 
     async def rechunk(self, job_id: str, chunking_options: dict) -> list[ChunkResult]:
@@ -115,6 +121,11 @@ class AnalysisService:
 
         return chunks
 
+    def _on_task_done(self, task: asyncio.Task, *, job_id: str) -> None:
+        """Cleanup running tasks and delegate to module-level handler."""
+        self._running_tasks.pop(job_id, None)
+        _on_task_done(task, job_id=job_id)
+
     async def _run_analysis(
         self,
         job_id: str,
@@ -235,6 +246,9 @@ def _on_task_done(task: asyncio.Task, *, job_id: str) -> None:
         _schedule_mark_failed(job_id, _classify_error(exc))
 
 
+# Keep the module-level function as the default, but AnalysisService uses its own method.
+
+
 def _schedule_mark_failed(job_id: str, error: str) -> None:
     """Schedule _mark_failed as a tracked background task."""
     t = asyncio.ensure_future(_mark_failed(job_id, error))
diff --git a/document-parser/tests/test_analysis_service.py b/document-parser/tests/test_analysis_service.py
index 66cbaac..a211dee 100644
--- a/document-parser/tests/test_analysis_service.py
+++ b/document-parser/tests/test_analysis_service.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import asyncio
+import functools
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
@@ -90,6 +91,60 @@ class TestOnTaskDone:
         mock_mark.assert_not_called()
 
 
+class TestAnalysisServiceCancellation:
+    """Verify delete cancels running tasks."""
+
+    @pytest.mark.asyncio
+    async def test_delete_cancels_running_task(self):
+        """Deleting a job while running should cancel its task."""
+        converter = MagicMock()
+        service = AnalysisService(converter=converter)
+
+        blocker = asyncio.Event()
+
+        async def slow_analysis():
+            await blocker.wait()
+
+        task = asyncio.create_task(slow_analysis())
+        service._running_tasks["j1"] = task
+
+        with patch("services.analysis_service.analysis_repo") as mock_repo:
+            mock_repo.delete = AsyncMock(return_value=True)
+            result = await service.delete("j1")
+
+        assert result is True
+        assert task.cancelling() or task.cancelled()
+        assert "j1" not in service._running_tasks
+
+    @pytest.mark.asyncio
+    async def test_delete_completed_job_no_error(self):
+        """Deleting a completed job should not raise even if no task tracked."""
+        converter = MagicMock()
+        service = AnalysisService(converter=converter)
+
+        with patch("services.analysis_service.analysis_repo") as mock_repo:
+            mock_repo.delete = AsyncMock(return_value=True)
+            result = await service.delete("j-gone")
+
+        assert result is True
+
+    @pytest.mark.asyncio
+    async def test_task_cleaned_from_running_on_completion(self):
+        """After a task completes, it should be removed from _running_tasks."""
+        converter = MagicMock()
+        service = AnalysisService(converter=converter)
+
+        async def instant():
+            pass
+
+        task = asyncio.create_task(instant())
+        service._running_tasks["j1"] = task
+        task.add_done_callback(functools.partial(service._on_task_done, job_id="j1"))
+        await task
+
+        assert "j1" not in service._running_tasks
+
+
 class TestAnalysisServiceConcurrency:
     """Verify that the semaphore limits concurrent analysis jobs."""