diff --git a/CHANGELOG.md b/CHANGELOG.md
index ef891aea9d..eb1ec56972 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -42,6 +42,8 @@ This project adheres to [Semantic Versioning](https://semver.org/).
   (#[1516](https://github.com/nix-rust/nix/pull/1516))
 - Added `Ipv4Ttl` and `Ipv6Ttl` sockopts.
   (#[1515](https://github.com/nix-rust/nix/pull/1515))
+- Added `MAP_EXCL` mmap flag for freebsd.
+  (#[1525](https://github.com/nix-rust/nix/pull/1525))
 
 ### Changed
 
diff --git a/src/sys/mman.rs b/src/sys/mman.rs
index ba6eb6619d..e3c36208bf 100644
--- a/src/sys/mman.rs
+++ b/src/sys/mman.rs
@@ -40,6 +40,10 @@ libc_bitflags!{
         MAP_PRIVATE;
         /// Place the mapping at exactly the address specified in `addr`.
         MAP_FIXED;
+        /// To be used with `MAP_FIXED`, to forbid the system
+        /// to select a different address than the one specified.
+        #[cfg(target_os = "freebsd")]
+        MAP_EXCL;
         /// Synonym for `MAP_ANONYMOUS`.
         MAP_ANON;
         /// The mapping is not backed by any file.