This chapter consists of an annotated checklist of living cartilaginous fishes that includes only described valid species but omits most synonyms and undescribed species. A generalized listing of geographic distribution and habitat is included for each genus. It is revised over previous published checklists as of June 11, 2004. Names of doubtful species are preceeded by a question mark; valid species that are doubtfully placed in agences have a question mark at the end of the generic name.