Background : Candida species are not only the leading cause of nosocomial fungal infections but also the important cause of infections in the immunocompromised hosts. Epidemiologic study of nosocomial candidiasis has been difficult because of the lack of a reliable typing system. We performed molecular epidemiologic study by using RFA and Southem hybridization for typing of candida isolates from patiients. Methods : A total of 27 candida isolates from 19 immunocompromised patients were studied. Morphotyping and biotyping were done by germ tube test and API 20C system, respectively. Candidial chromosomal DNA was extracted, digested with EcoRI, HindalII and RFA was done. Southem hybridization of chromosomal DNA was also done with digoxigen-labelled Candial albicans-specific DNA probe. Results : The time-period of development of oral candidiasis after admission was 5-14 days (mean : 8 days). C.albicans was the most common species (19), followed by C tropiadis (2), C glabn#zta (2), C.paratropicalis (2), and C parapsilosis (1). The subtypes of Candida species by RFA of chromosomal DNA were C. albieans, 12 types , C tropicalis, 2 types, C glabrata, 2 types ; C.parapsilasis, 1 type ; C. paratropicalis, 1 type. For 7 (87.5%) of 8 patients, RFA pattern of one isolate was identical to that of the other isolates. Conclusion : RFA of candidial chromosomal DNA results were obtainable within days. RFA showed high reproducibility, typeability and good discrimination power between isolates, provided a robust system that may be used rapidly to identify outbreaks of nosocomial candidiasis.