The desiccation tolerance of three mycophagous Drosophila species was measured by enclosing sets of 20 sexed flies in Drosophila vials with 2 g of Drierite® calcium sulfate desiccant at 23 C and recording the time until 10 flies were dead (LT₅₀). Female D. putrida were the most desiccation tolerant; they had LT₅₀ periods (X̄ ± 1, sd = 21.55 ± 1.36 h) twice as long as male D. putrida and males and females of D. falleni and D. tripunctata. Although D. putrida had the lowest initial wet mass, it had significantly higher percentage body water and lost a smaller percentage of body water at LT₅₀ than the other species. These differences in desiccation tolerance may explain, in part, why D. putrida is more abundant than the other species in dry habitats or during dry periods.