The great diversity of arthropod body plans, together with our detailed understanding of fruit fly development, makes arthropods a premier taxon for examining the evolutionary diversification of developmental patterns and hence the diversity of extant life. Crustaceans, in particular, show a remarkable range of morphologies and provide a useful outgroup to the insects. The amphipod crustacean Parhyale hawaiensis is becoming established as a model organism for developmental studies within the arthropods. This protocol describes the dissection and fixation of P. hawaiensis embryos. Embryonic tissue fixed in the following manner is suitable for in situ hybridization experiments to study mRNA expression or for immunocytochemistry to study protein localization.