diff --git a/ext/cbson/cbson.c b/ext/cbson/cbson.c
index d5adb97..3f15a32 100644
--- a/ext/cbson/cbson.c
+++ b/ext/cbson/cbson.c
@@ -31,14 +31,14 @@
 #  define RSTRING_LEN(v) RSTRING(v)->len
 #endif
 #ifndef RSTRING_LENINT
-#  define RSTRING_LENINT(v) rb_long2int(RSTRING_LEN(v))
+#  define RSTRING_LENINT(v) (int)(RSTRING_LEN(v))
 #endif
 
 #ifndef RARRAY_LEN
 #  define RARRAY_LEN(v) RARRAY(v)->len
 #endif
 #ifndef RARRAY_LENINT
-#  define RARRAY_LENINT(v) rb_long2int(RARRAY_LEN(v))
+#  define RARRAY_LENINT(v) (int)(RARRAY_LEN(v))
 #endif
 
 #if HAVE_RUBY_ST_H