Several species of the genus Aphidius are used in biological control programs against aphid pests throughout the world and their behavior and physiology are well studied. While the importance of sensory organs in their behavior is understood, their antennal structure remains largely unknown. In this study, the external morphology and distribution of the antennal sensilla on the antennal of both female and male adults of A. colemani were described using scanning electron microscopy (SEM). Generally, the filiform antennae of males (1,515.2±116.5 ㎛) are longer than females (1,275.1±103.4 ㎛). Antennae of this species are made up of radicle, scape, pedicel and flagellomeres. Male and female antennae differed in the total number of flagellomeres as 15 in males and 13 in females. The result of SEM observation was characterization and grouping of seven types of receptors into morphological classes: Bohm bristles, Sensilla placodea, 2 types of S. coeloconica and S. trichodea, and S. basiconica as with a tip pore and with wall pores. In addition, the possible functions of the above sensilla types are discussed in light of previously published literature, mechanoreception (Bohm bristles, S. coeloconica Ⅰ & Ⅱ and S. trichodea) and chemoreception (S. placodea, S. basiconica type Ⅰ & Ⅱ).