diff --git a/src/option_parser.cpp b/src/option_parser.cpp
index a4922c8c..39be7a85 100644
--- a/src/option_parser.cpp
+++ b/src/option_parser.cpp
@@ -235,6 +235,10 @@ _option_processor(void       *data_,
       else
         return ::_process_mount(arg_);
 
+    case MERGERFS_OPT_DEBUG:
+      cfg.debug = true;
+      break;
+
     case MERGERFS_OPT_HELP:
       ::_usage();
       exit(0);