A commercial fishery for the smooth hammerhead shark (Sphyrna zygaena) exists in the waters off northern Peru. Although international and domestic norms regulate this species, adult specimens are becoming rare. Monthly visits to four ports in the La Libertad region were made to measure S. zygaena landings and understand the present state of the fishery. We found that 92% of the specimens landed were juveniles or younger and that 10% of the original biomass remains in the fishery. This highlights that stricter regulations such as protecting breeding areas, establishing a legal catch length, and limiting the catch volume and fishing season are urgently needed to maintain a sustainable fishery.