Studies of oviposition behavior on Anastrepha fratercu'lus (Wiedmann, 1830)(Diptera, Tephri tidae) in natural and lab conditions-Toe oviposition behavior of Anastrepha fraterculus was car ried out at natural and lab conditions. ln natural conditions it was observed 4 stages: a) female arriving on fruit; b) searching at adequate site; c) oviposition, and d) ovipositor dragging. At lab this pattern was alterated, including in most cases absence of oviposition behavior. The mean duration in minutes and seconds of different stages are presented and its ecological role discussed.