While socioeconomic factors have been found to be important in the incidence of head lice (Pediculosis capitis) infestation, most reports pertain to children. Furthermore, it is not clear whether similar factors are correlated with infestation with pubic lice (Phthirus pubis). We examined the association of two measures of socioeconomic status with each condition in a random sample of 500 notifications of each condition in the Israel Defense Forces. Since head lice were predominantly reported in females, and pubic lice predominantly in males, the analyses for head lice were restricted to females (474 cases) and those for pubic lice to males (481 cases). A significant negative association was found between both the number of years of formal education and a measure of socioeconomic status with infestation with both head and pubic lice. These findings suggest that among adults, both types of infestation are more common in the lower socioeconomic groups, and this should be taken into account when designing public health campaigns to control these problems.