diff --git a/src/unix/haiku/mod.rs b/src/unix/haiku/mod.rs
index 24aa599c07070..b1036cdc5eb91 100644
--- a/src/unix/haiku/mod.rs
+++ b/src/unix/haiku/mod.rs
@@ -741,6 +741,7 @@ pub const RLIMIT_AS: ::c_int = 6;
 pub const RLIM_INFINITY: ::rlim_t = 0xffffffff;
 // Haiku specific
 pub const RLIMIT_NOVMON: ::c_int = 7;
+#[deprecated(since = "0.2.64", note = "Not stable across OS versions")]
 pub const RLIM_NLIMITS: ::c_int = 8;
 
 pub const RUSAGE_SELF: ::c_int = 0;
diff --git a/src/unix/nto/mod.rs b/src/unix/nto/mod.rs
index a79450f4e1fd2..de972a065ab2b 100644
--- a/src/unix/nto/mod.rs
+++ b/src/unix/nto/mod.rs
@@ -2557,6 +2557,7 @@ pub const RLIMIT_NPROC: ::c_int = 8;
 pub const RLIMIT_RSS: ::c_int = 6;
 pub const RLIMIT_STACK: ::c_int = 3;
 pub const RLIMIT_VMEM: ::c_int = 6;
+#[deprecated(since = "0.2.64", note = "Not stable across OS versions")]
 pub const RLIM_NLIMITS: ::c_int = 14;
 
 pub const SCHED_ADJTOHEAD: ::c_int = 5;