The mango fruit cv. ‘Ataulfo’ niño is an underdeveloped fruit that has a split on the back and a pronounced peak, and among the current total supply of commercialized mangoes cv. ‘Ataulfo’, approximately 2% are classified as ‘Ataulfo’ niño, which are strongly infested by Anastrepha ludens (Loew) (Diptera: Tephritidae) and Anastrepha obliqua Mcquart. The objective of this study was to determine the tolerance to 150-Gy generic irradiation for fruit flies of the Anastrepha genus in comparison to the development of a hot water treatment (HWT) as phytosanitary treatments for mango fruits cv. ‘Ataulfo’ niño infested by A. ludens and A. obliqua. The results indicated that both treatments were effective; 150-Gy irradiation and HWT at 46.3–47°C for 51 min did not result in significant effects on the external and internal color, total sugar content, firmness, pH, or weight. The sensorial quality described by the appearance, flavor, color, and odor did not show any significant differences between treatments. For both A. ludens and A. obliqua, the third larval instar was the most thermotolerant. The efficacy test was conducted with an immersion time of 47 min. A. ludens did not survive, but for A. obliqua, three larvae out of a total of 6,890 did survive and pupate. Consequently, the confirmatory test consisted of submerging mangoes infested with third-instar A. ludens and A. obliqua in water at 46.3–47°C for 51 min. In total, 67,392 A. ludens and 22,086 A. obliqua larvae were treated, and no surviving larvae were observed.