diff --git a/rand_core/CHANGELOG.md b/rand_core/CHANGELOG.md
index 84c40cf9aa..15a16704d8 100644
--- a/rand_core/CHANGELOG.md
+++ b/rand_core/CHANGELOG.md
@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## Unreleased
 ### API changes
 - Relax `Sized` bound on impls of `SeedableRng` (#1641)
+- Fix `OsError::raw_os_error` on UEFI targets by returning `Option<usize>` (#1665)
 - Move `rand_core::impls::*` to `rand_core::le` module (#1667)
 - Use Edition 2024 and MSRV 1.85 (#1668)
 - Remove fn `TryRngCore::read_adapter(..) -> RngReadAdapter` (replaced with `rand::RngReader`) (#1669)
diff --git a/rand_core/src/os.rs b/rand_core/src/os.rs
index 49111632d9..dc4125c960 100644
--- a/rand_core/src/os.rs
+++ b/rand_core/src/os.rs
@@ -66,6 +66,14 @@ impl std::error::Error for OsError {
     }
 }
 
+// If [`RawOsError`](https://doc.rust-lang.org/std/io/type.RawOsError.html) is stablized, we can use it.
+
+#[cfg(not(target_os = "uefi"))]
+type RawOsError = i32;
+
+#[cfg(target_os = "uefi")]
+type RawOsError = usize;
+
 impl OsError {
     /// Extract the raw OS error code (if this error came from the OS)
     ///
@@ -75,7 +83,7 @@ impl OsError {
     ///
     /// [1]: https://doc.rust-lang.org/std/io/struct.Error.html#method.raw_os_error
     #[inline]
-    pub fn raw_os_error(self) -> Option<i32> {
+    pub fn raw_os_error(self) -> Option<RawOsError> {
         self.0.raw_os_error()
     }
 }