The avifauna of the island of Flores (Lesser Sunda Islands) is reviewed. Introductory sections, which include a chapter on the history of ornithological discovery, are followed by the main part, a systematic account in which each species and subspecies known from Flores is treated separately. A discussion of the zoogeography, a gazetteer, a list of references and an index complete the volume. At present 214 forms (210 species) are accepted as having been reliably recorded. Of these, ca. 160 are, or may be assumed to be, residents, and of ca. 100 the eggs have been collected and are described. The balance consists of visiting sea and freshwater birds, migrants from the North and migrants from the South. It is likely that few additions remain to be made to the list of residents, but migrants from the North and visiting seabirds have obviously been under-recorded, and in these two categories another 20 to 25 species are to be expected as regular visitors. Lonchura punctulata insulicola subspec. nov. is described from Mauritius, Réunion and Mahé (Seychelles Is.).