diff --git a/src/Init/System/IO.lean b/src/Init/System/IO.lean
index 0cf0ffd6f1..dd468f3e7b 100644
--- a/src/Init/System/IO.lean
+++ b/src/Init/System/IO.lean
@@ -133,11 +133,6 @@ constant Handle.read  (h : @& Handle) (bytes : USize) : IO ByteArray := arbitrar
 @[extern "lean_io_prim_handle_write"]
 constant Handle.write (h : @& Handle) (buffer : @& ByteArray) : IO Unit := arbitrary _
 
-@[extern "lean_io_prim_handle_read_byte"]
-constant Handle.getByte  (h : @& Handle) : IO UInt8 := arbitrary _
-@[extern "lean_io_prim_handle_write_byte"]
-constant Handle.putByte (h : @& Handle) (c : UInt8) : IO Unit := arbitrary _
-
 @[extern "lean_io_prim_handle_get_line"]
 constant Handle.getLine (h : @& Handle) : IO String := arbitrary _
 @[extern "lean_io_prim_handle_put_str"]
@@ -178,8 +173,6 @@ def Handle.isEof : Handle → m Bool := Prim.liftIO ∘ Prim.Handle.isEof
 def Handle.flush : Handle → m Unit := Prim.liftIO ∘ Prim.Handle.flush
 def Handle.read (h : Handle) (bytes : Nat) : m ByteArray := Prim.liftIO (Prim.Handle.read h (USize.ofNat bytes))
 def Handle.write (h : Handle) (s : ByteArray) : m Unit := Prim.liftIO (Prim.Handle.write h s)
-def Handle.getByte (h : Handle) : m UInt8 := Prim.liftIO (Prim.Handle.getByte h)
-def Handle.putByte (h : Handle) (b : UInt8) : m Unit := Prim.liftIO (Prim.Handle.putByte h b)
 
 def Handle.getLine : Handle → m String := Prim.liftIO ∘ Prim.Handle.getLine
 
diff --git a/src/runtime/io.cpp b/src/runtime/io.cpp
index e7f45fc904..d7dfc485e9 100644
--- a/src/runtime/io.cpp
+++ b/src/runtime/io.cpp
@@ -275,27 +275,6 @@ extern "C" obj_res lean_io_prim_handle_flush(b_obj_arg h, obj_arg /* w */) {
     }
 }
 
-/* Handle.readByte : (@& Handle) → IO UInt8 */
-extern "C" obj_res lean_io_prim_handle_read_byte(b_obj_arg h, obj_arg /* w */) {
-    FILE * fp = io_get_handle(h);
-    int c = std::fgetc(fp);
-    if (c != EOF) {
-        return set_io_result(box(c));
-    } else {
-        return set_io_error(decode_io_error(errno, nullptr));
-    }
-}
-
-/* Handle.writeByte : (@& Handle) → UInt8 → IO unit */
-extern "C" obj_res lean_io_prim_handle_write_byte(b_obj_arg h, uint8 c, obj_arg /* w */) {
-    FILE * fp = io_get_handle(h);
-    if (std::fputc(c, fp) != EOF) {
-        return set_io_result(box(0));
-    } else {
-        return set_io_error(decode_io_error(errno, nullptr));
-    }
-}
-
 static object * g_io_error_eof = nullptr;
 
 /* Handle.read : (@& Handle) → USize → IO ByteArray */