diff --git a/datamasque/client/runs.py b/datamasque/client/runs.py
index 6b9a827..c25317e 100644
--- a/datamasque/client/runs.py
+++ b/datamasque/client/runs.py
@@ -1,5 +1,6 @@
 import logging
 import re
+from typing import Union
 
 from datamasque.client.base import BaseClient
 from datamasque.client.exceptions import (
@@ -43,9 +44,12 @@ def get_run_report(self, run_id: RunId) -> str:
         response = self.make_request("GET", f"api/runs/{run_id}/run-report/")
         return response.text
 
-    def get_db_discovery_result_report(self, run_id: RunId, include_selection_column: bool = True) -> str:
+    def get_db_discovery_result_report(self, run_id: RunId, include_selection_column: bool = True) -> Union[str, bytes]:
         """
-        Returns the database-discovery result report for the specified run as CSV.
+        Returns the database-discovery result report for the specified run.
+
+        Returns CSV text (`str`), or a zip of numbered CSV parts as `bytes` when the report is
+        large enough that the server splits it.
 
         When `include_selection_column` is true (the default),
         the CSV includes a `selected` column suitable for feeding back into ruleset generation.
@@ -54,6 +58,9 @@ def get_db_discovery_result_report(self, run_id: RunId, include_selection_column
         url = f"api/runs/{run_id}/db-discovery-results/report/"
         params = None if include_selection_column else {"include_selection_column": "false"}
         response = self.make_request("GET", url, params=params)
+
+        if response.headers.get("X-DM-Download-Format") == "zip":
+            return response.content
         return response.text
 
     def get_unfinished_runs(self) -> dict[str, UnfinishedRun]:
diff --git a/tests/test_discovery.py b/tests/test_discovery.py
index 2830287..ff2b1ed 100644
--- a/tests/test_discovery.py
+++ b/tests/test_discovery.py
@@ -93,6 +93,17 @@ def test_get_db_discovery_result_report(client):
         assert result == "db discovery report without selection column"
 
 
+def test_get_db_discovery_result_report_returns_zip_bytes_when_split(client):
+    run_id = RunId(1)
+    zip_bytes = b"PK\x03\x04 split report zip bytes"
+    with requests_mock.Mocker() as m:
+        url = f"http://test-server/api/runs/{run_id}/db-discovery-results/report/"
+        m.get(url, content=zip_bytes, headers={"X-DM-Download-Format": "zip"}, status_code=200)
+        result = client.get_db_discovery_result_report(run_id)
+        assert result == zip_bytes
+        assert isinstance(result, bytes)
+
+
 def test_poll_async_ruleset_generation(client):
     connection_id = ConnectionId("1")
     with requests_mock.Mocker() as m: