A method for the rapid presumptive differentiation of a panel of 12 clinically relevant yeasts to the species level was developed on the basis of evaluation by the polymerase chain reaction (PCR) of the gene coding for the small ribosomal subunit 18S-rRNA. The method involved restriction enzyme analysis of PCR products obtained with primers common to all fungi. Using six restriction enzymes, AluI, BanI, BbsI, DraII, Eco147I and NheI, characteristic PCR-restriction enzyme patterns were obtained for Candida albicans, Candida tropicalis, Candida krusei, Candida kefyr, Candida lusitaniae, Candida guilliermondii, Candida glabrata and Saccharomyces cerevisiae, as well as for the pairs Candida parapsilosis/Candida viswanathii and Trichosporon beigelii/Cryptococcus neoformans. The procedure does not involve hybridization steps or the use of radioactivity and can be completed within one working day.