Resumo. Fruit flies are insects with a high destructive potential and require a management and control plan in various fruit crops. Among them, pitaya cultivation (Selenicereus undatus (Haw.) D.R. Hunt – Cactaceae), which has been increasing in the state of Mato Grosso do Sul e in the all Brazil. Pitaya containing Diptera larvae were collected in the municipality of Costa Rica, state of Mato Grosso do Sul, Brazil and taken to the laboratory to adult insect obtention. The adults emerged was identified as Anastrepha obliqua (Macquart, 1835) (Diptera: Tephritidae). This work is the first report of A. obliqua associated with pitaya fruits in Brazil.