Crustaceans are an important component in the diet of numerous predators of the Southern Ocean (water masses located south of the Subtropical Front). As identifying crustaceans from food samples using conventional methods is not easy, a crustacean guide was written to aid scientists working on trophic relationships within the Southern Ocean. Having the needs of the scientists in mind, we gathered information from > 100 species from 53 families of the most relevant crustaceans in the diet of subantarctic and Antarctic meso- and top predators, including information on distribution, their relevance in predator diets, sizes, availability of allometric equations and practical procedures to differentiate crustacean species within each family. Additional information of bibliography is added if families possess more that the species mentioned in this book. It is noted that a large number of species still has no allometric equations and some species have to clarify their status (one or various species). The book was produced within the international effort under the Scientific Committee on Antarctic Research (SCAR) programs, expert and action groups, namely SCAR AnT-ERA, SCAR AnT-ECO, SCAR EGBAMM and ICED.