diff --git a/csv_metadata_quality/app.py b/csv_metadata_quality/app.py
index f06d1dc..9d87996 100644
--- a/csv_metadata_quality/app.py
+++ b/csv_metadata_quality/app.py
@@ -88,3 +88,7 @@ def run(argv):
 
     # Write
     df.to_csv(args.output_file, index=False)
+
+    # Close the input and output files before exiting
+    args.input_file.close()
+    args.output_file.close()