We seek for general responses to salinity in larval growth, biomass and chemical composition (protein, lipid) of twelve species of decapod crustaceans varying in euryhalinity and osmoregulatory capabilities (from osmoconformers to strong osmoregulators). Data for seven species were obtained from previous publications; those for five additional species are reported for the first time. The biomass of euryhaline larval instars showed consistently a weak response to salinity, even near the lower limits of salinity tolerance. Biomass of stenohaline larval instars showed a higher sensibility to salinity variations, with strong interspecific variability. The sensibility decreased with increasing osmoregulatory capacity. Our data suggest that euryhalinity is associated with a reduced sensibility of metabolic and growth processes to low salinity. The ability to osmoregulate buffers the internal medium allowing the larvae to maintain a high growth rate. The energetic costs of osmoregulation in larval decapods seem to be offset by the capacity of maintaining high growth rates in physically variable environments.