The distribution of the subterranean life stages of the grape root borer,Vitacea polistiformis(Harris), were estimated by sampling 2 habitat units; a unit of the soil surface for pupae and a unit of the grape root system for larvae. Pupae were distributed evenly around the trunk base with no significant angular orientation. Pupal density decreased exponentially from the trunk base to the periphery of the sample unit. The mean distance of the pupae from the trunk base ranged from 12.8–17.1 cm at 4 sites with no significant difference between male and female pupae. The sex ratio (♂/♀) ranged from 0.62–1.27 at these sites. The distribution of larvae in 3 size classes was modeled by multiple regression equations which related larval density to concomitant values of depth in the soil, distance from the trunk base and diam of the inhabited root. Small larvae were distributed evenly throughout the sample unit, whereas medium and large larvae had distributions skewed toward the larger roots and the trunk base of the vine.