A two-and-a-half month fish-collecting expedition to the Chagos Archipelago yielded specimens of 98 species (in 36 genera) of gobioid fishes. Ninety species belong to the Gobiidae, three to the Eleotrididae, one to the Kraemeriidae , and four to the Microdesmidae. Additional species, not collected by us, are Paragunnellichthys fehlmani (Microdesmidae), described from five specimens collected at Diego Garcia, and