diff --git a/hazimp/jobs/jobs.py b/hazimp/jobs/jobs.py
index fa90b71..1f5cec4 100755
--- a/hazimp/jobs/jobs.py
+++ b/hazimp/jobs/jobs.py
@@ -735,7 +735,7 @@ def __call__(self, context, filename=None, boundaries=None,
                  fields=None, use_parallel=True):
         # Default filename to use when no output filename is specified
         if filename is None:
-            filename = 'output.shp'
+            filename = 'output.json'
 
         # Defaults fields to use when none are provided to maintain
         # backwards compatibility
diff --git a/tests/jobs/test_jobs.py b/tests/jobs/test_jobs.py
index fdd257e..429bd40 100755
--- a/tests/jobs/test_jobs.py
+++ b/tests/jobs/test_jobs.py
@@ -772,7 +772,7 @@ def test_default_aggregate_filename(self):
         instance(context, None, 'boundaries.json', 'MESHBLOCK_CODE_2011', 'MB_CODE11', True, {}, False)
 
         context.save_aggregation.assert_called_once_with(
-            'output.shp', 'boundaries.json', 'MESHBLOCK_CODE_2011', 'MB_CODE11', True, {}, use_parallel=False
+            'output.json', 'boundaries.json', 'MESHBLOCK_CODE_2011', 'MB_CODE11', True, {}, use_parallel=False
         )
 
     def test_default_aggregate_fields(self):