External morphology of antennal sensilla of both sexes of irradiated with sterilizing and substerilizing doses and unirradiated peach fruit fly, Bactrocera zonata were studied with scanning electron microscopy. The antenna of this fly consists of 3 segments: Basal scape, pedicel and funiculus. The antennal segments of males tended to be longer and more elongated than those of females. Eight distinct morphological types of sensilla belong to four groups. These sensilla are: trichoid sensilla type I and II, chaetica sensilla type I and II, basiconic sensilla type I, II, III and campaniform sensilla (in the pedicel of female). The changes which occurred to the antennae and their associated sensilla due to the sterilizing dose (90Gy for male and 50Gy for female) were investigated; distribution, size and position are also described.