diff --git a/run.py b/run.py
index c13f4c45..13f9b67d 100644
--- a/run.py
+++ b/run.py
@@ -7,6 +7,8 @@
 """
 
 import click  #type: ignore
+import os
+import sys
 from kg_obo.transform import run_transform
 
 @click.command()
@@ -29,7 +31,11 @@
                is_flag=True,
                help="If used, upload to S3 bucket is tested only.")
 def run(skip, get_only, bucket, save_local, s3_test):
-  run_transform(skip, get_only, bucket, save_local, s3_test)
+    if os.path.isfile("lock"):
+        sys.exit("KG-OBO is already running. Exiting...")
+    else:
+        lockfile = open
+        run_transform(skip, get_only, bucket, save_local, s3_test)
 
 if __name__ == '__main__':
   run()