diff --git a/benches/benches.rs b/benches/benches.rs
index 19ca8ea..682f915 100644
--- a/benches/benches.rs
+++ b/benches/benches.rs
@@ -32,7 +32,7 @@ fn bench_probe_wdl(bench: &mut Bencher) {
     });
 }
 
-#[cfg(feature = "mmap")]
+#[cfg(all(feature = "mmap", target_pointer_width = "64"))]
 fn bench_probe_wdl_mmap(bench: &mut Bencher) {
     // Safety: No modifications to table files and I/O errors please.
     // Fingers crossed.
@@ -55,9 +55,9 @@ fn bench_probe_wdl_mmap(bench: &mut Bencher) {
     });
 }
 
-#[cfg(not(feature = "mmap"))]
+#[cfg(not(all(feature = "mmap", target_pointer_width = "64")))]
 benchmark_group!(benches, bench_add_directory, bench_probe_wdl);
-#[cfg(feature = "mmap")]
+#[cfg(all(feature = "mmap", target_pointer_width = "64"))]
 benchmark_group!(
     benches,
     bench_add_directory,
diff --git a/src/tablebase.rs b/src/tablebase.rs
index a1ba53e..6a8fae9 100644
--- a/src/tablebase.rs
+++ b/src/tablebase.rs
@@ -80,7 +80,7 @@ impl<S: Position + Clone + Syzygy> Tablebase<S> {
     /// * Externally guarantee absence of I/O errors (or live with the
     ///   consequences). For example, I/O errors will generate
     ///   `SIGSEV`/`SIGBUS` on Linux.
-    #[cfg(feature = "mmap")]
+    #[cfg(all(feature = "mmap", target_pointer_width = "64"))]
     pub unsafe fn with_mmap_filesystem() -> Tablebase<S> {
         // Safety: Forwarding contract of memmap2::MmapOptions::map()
         // to caller.
diff --git a/tests/suite.rs b/tests/suite.rs
index b1f0cac..06f5268 100644
--- a/tests/suite.rs
+++ b/tests/suite.rs
@@ -63,7 +63,7 @@ fn test_chess() {
     test_csv::<Chess>(Tablebase::new(), "tests/chess.csv");
 }
 
-#[cfg(feature = "mmap")]
+#[cfg(all(feature = "mmap", target_pointer_width = "64"))]
 #[test]
 fn test_chess_mmap() {
     // Safety: No modifications to table files and I/O errors please.