The change in carriage rates of Pilyrosporum sp. over the years before and after puberty were studied in Caucasoid and Negroid children using a semiquantitative cultural technique. Caucasoids yielded yeasts more often than did negroids; older or sexually mature children yielded yeasts more often than did prepubertal children. There appeared to be a decrease in numbers of yeasts isolated a few years after the pubertal peak.