Bryozoans are encrusting colonial organisms which are ubiquitous in freshwater and marine environments. As the dominant sessile organisms of the Antarctic shelf seas, they are a pivotal component of the ecosystem. This is the first identification guide to the Bryozoa and describes and illustrates all 264 species of cheilostomate Bryozoa which have been recorded from the Antarctic seas. It includes an illustrated dichotomous key to the genera, and for each genus there is a key to Antarctic species. Allspecies are fully described, and a clear diagnosis is given for each genus, family, and superfamily.