The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), is one of the most important quarantine pests in the world. Host commodities shipped from infested parts of the world to non-infested parts that might be susceptible to infestation should undergo a phytosanitary measure to render negligible the risk of shipping viable flies. Ionizing irradiation is a promising phytosanitary treatment that is tolerated by the great majority of hosts of the Mediterranean fruit fly. The current dose in the US is 150 Gy. This research conducted with cage-infested ‘Haden’ mangoes in Peru showed that 100 Gy is sufficient to provide a high level of quarantine security against this important pest. That dose did not affect pupation when applied to late 3rd instars, but it did prevent any from emerging as adults. A dose of 100 Gy might allow for irradiation of avocados, one of the few fruits that does not tolerate more than 100-200 Gy.