Montiel returned to the super flyweight division and continued defending his title by defeating Z Gorres (26–1–1), Cecilio Santos (22–7–2), Luis Melendez (25–2–1), and former champion Martín Castillo (33–2–0).
On March 28, 2009, he defeated Diego Oscar Silva (24–1–3) by third round knock out to win the Interim WBO Bantamweight title.
[3] On September 12, 2009, Montiel faced fellow Mexican Alejandro Valdez (21–3–2) at the Palenque de la Feria in Tepic, Nayarit.
On February 13, 2010, Montiel defeated Filipino prospect Ciso Morales (14–0) via KO at the 1st round, successfully defending his WBO Bantamweight title.
Montiel, who was a heavy underdog leading up to the bout, knocked out Hasegawa in the fourth round, putting an end to the Japanese fighter's 5-year title reign.
[6] On October 4, 2010, promoter Bob Arum announced that Fernando Montiel and Nonito Donaire are on course for a February 19, 2011 bout.
He rebounded with wins over future champion Nehomar Cermeno and Alvaro Perez, then faced Victor Terrazas for the vacant WBC Silver Super Bantamweight title, but was defeated by 12 round decision in what was considered an upset.