Nineteen different species belonging to the genus Oryza were studied for variation in electrophoretic patterns of alcohol dehydrogenase (ADH) extracted from germinating seeds. The ADH patterns were similar for aerobically and anaerobically germinating seeds of all the species. Oryza saliva accessions, both indica and japonica, revealed a five-band pattern on polyacrylamide gels. African cultivated rice, Oryza glaberrima, had an alcohol dehydrogenase pattern similar to that of O. sativa. Oryza perennis complex comprising of Oryza nivara, Oryza rufipogon in Asia, Oryza barthii, Oryza longistaminata in Africa, and some of the accessions of O. rufipogon from America had ADH patterns similar to that of O. sativa. In a few accessions of O. rufipogon from America, only three bands were visualized. Oryza minuta, Oryza officinalis, Oryza punctata, Oryza alta, Oryza grandiglumis, and Oryza latifolia had similar patterns with one major band at the same Rf value as the major band of O. sativa and two minor bands corresponding to the two bands found in O. sativa. Oryza australiensis, Oryza brachyantha, and Oryza granulata had distinct patterns. Oryza ridleyi had a six-band pattern with three major and three minor bands. The three major bands correspond to the major band of O. granulata, O. officinalis, and O. australiensis. Based on alcohol dehydrogenase data, six major groups were identified amongst Oryza species. Key words: Oryza species, alcohol dehydrogenase, phylogenetics.