During a 15-day period, 7 premature infants hospitalized in a neonatal intensive care unit presented with sepsis caused by Candida albicans. The local environment and hands of all 54 persons involved in the intensive care unit were examined for the presence of this organism. Five techniques were used in the analysis of the isolates recovered from blood cultures of the children, the hands of personnel and 10 control isolates. The methods used were serotype determination, genetic fingerprinting, morphotyping, resistotyping and killer yeast typing. Morphotyping and genetic fingerprinting proved to be the most discriminatory techniques, and only combined analysis of the results obtained with these various methods allowed the source of the outbreak to be identified. An isolate from the hands of a healthy staff member and isolates from infected children all belonged to the same strain.