diff --git a/doc/api/fs.md b/doc/api/fs.md
index 345d0225ee4d0b..8ad43dacaa1edb 100644
--- a/doc/api/fs.md
+++ b/doc/api/fs.md
@@ -1953,7 +1953,7 @@ changes:
 -->
 
 * `fd` {integer}
-* `mode` {integer}
+* `mode` {string|integer}
 * `callback` {Function}
   * `err` {Error}
 
@@ -1966,7 +1966,7 @@ added: v0.4.7
 -->
 
 * `fd` {integer}
-* `mode` {integer}
+* `mode` {string|integer}
 
 Synchronous fchmod(2). Returns `undefined`.