As part of a current effort to restore the Salish Sea, a 16,925-km2 inland waterway shared by Washington State and British Columbia, a definitive, up-to-date list of the fishes that inhabit this marine ecosystem has been badly needed. The last such effort was published more than three decades ago. In response to this deficiency, we compiled information from various sources and identified 253 fish species observed in marine or brackish waters of the Salish Sea ecosystem, an increase of nearly 14% since the last published checklist. These 253 species, encompassing 1 myxinid, 2 petromyzontids, 18 chondrichthyans, 2 chondrosteans, and 230 teleosts, are contained within 78 families and 31 orders. This comprehensive list of the Salish Sea ichthyofauna will serve as a foundation for determining the occurrence of new species and perhaps the disappearance of others, enabling the selection of species as indicators of ecosystem health, and will provide a basis for identifying the mechanisms responsible for marine animal declines.