diff --git a/include/pocketpy/pocketpy.h b/include/pocketpy/pocketpy.h
index 2a35dc85..f2401dc7 100644
--- a/include/pocketpy/pocketpy.h
+++ b/include/pocketpy/pocketpy.h
@@ -105,6 +105,7 @@ bool py_tobool(const py_Ref);
 py_Type py_totype(const py_Ref);
 const char* py_tostr(const py_Ref);
 const char* py_tostrn(const py_Ref, int* size);
+const unsigned char* py_tobytes(const py_Ref, int* size);
 
 void* py_touserdata(const py_Ref);
 
diff --git a/src/public/cast.c b/src/public/cast.c
index 97668e46..6634d7d1 100644
--- a/src/public/cast.c
+++ b/src/public/cast.c
@@ -51,6 +51,13 @@ const char* py_tostrn(const py_Ref self, int* size){
     return py_Str__data(ud);
 }
 
+const unsigned char* py_tobytes(const py_Ref self, int* size){
+    assert(self->type == tp_bytes);
+    int* ud = PyObject__value(self->_obj);
+    *size = *ud;
+    return (unsigned char*)(ud + 1);
+}
+
 void* py_touserdata(const py_Ref self){
     assert(self && self->is_ptr);
     return PyObject__value(self->_obj);