diff --git a/run.sh b/run.sh
index ee64263..49b8dc9 100644
--- a/run.sh
+++ b/run.sh
@@ -71,7 +71,7 @@ else
     exit 8
 fi
 
-if [[ $GENERATE_DHPARAM = true ]]
+if [[ $GENERATE_DHPARAM = true ]] && [[ ! -s /config/letsencrypt/keys/ssl-dhparams.pem ]]
 then
     echo "Generating Diffie-Hellman keys, saved to /config/letsencrypt/keys"
     openssl dhparam -out /config/letsencrypt/keys/ssl-dhparams.pem 4096