1. 1. The rates of oxygen consumption by the first and second zoeae and early post-metamorphic and non-ovigerous, adult female mole crabs. Emerita brasiliensis Schmitt, were measured at 15, 20, 25 and 30°C using Cartesian diver and Warburg respirometers. 2. 2. Weight specific oxygen consumption rates (μ10 2 mg dry wt −1. h −1) decreased from the first zoea through subsequent developmental stages to the adult female. 3. 3. Zoeal metabolism increased steadily from 15 to 25 C, declining sharply at 30 C; rates for the post-metamorphic stage and adult females, in contrast, increased over the entire temperature range used. 4. 4. Metabolic rates of zoeae I and II and the post-metamorphic stage showed highest Q 10 values between 20 and 25°C while the adult female showed a maximum Q 10 value between 15 and 20 C.