diff --git a/src/io_uring.rs b/src/io_uring.rs
index 7be65705e..09a4d6d62 100644
--- a/src/io_uring.rs
+++ b/src/io_uring.rs
@@ -121,6 +121,9 @@ bitflags::bitflags! {
         /// `IORING_ENTER_EXT_ARG`
         const EXT_ARG = sys::IORING_ENTER_EXT_ARG;
 
+        /// `IORING_ENTER_REGISTERED_RING`
+        const REGISTERED_RING = sys::IORING_ENTER_REGISTERED_RING;
+
         /// <https://docs.rs/bitflags/latest/bitflags/#externally-defined-flags>
         const _ = !0;
     }