diff --git a/redash/query_runner/pg.py b/redash/query_runner/pg.py
index b9ca5eebd5..2aab3f2ad8 100644
--- a/redash/query_runner/pg.py
+++ b/redash/query_runner/pg.py
@@ -165,7 +165,7 @@ def run_query(self, query, user):
 
                 data = {'columns': columns, 'rows': rows}
                 error = None
-                json_data = json_dumps(data)
+                json_data = json_dumps(data, ignore_nan=True)
             else:
                 error = 'Query completed but it returned no data.'
                 json_data = None