Candida dubliniensis is a newly recognized species closely phylogenetically related to Candida albicans and is commonly associated with oral candidiasis in human immunodeficiency virus-positive patients. In this paper we report the isolation of three strains of C. dubliniensis, from AIDS patients, in the state of Rio Grande do Sul (Brazil). The phenotypic identification was based on germ tube emission, abundant production of chlamydospores, assimilation of sucrose but not of xylose and the inability to grow at 42 degrees C. Randomly amplified polymorphic DNA (RAPD) analysis and genomic DNA sequencing confirmed the distinct genetic nature C. dubliniensis. Topics related to the epidemiology, isolation, phenotypical and genotypical identification of C. dubliniensis are also discussed.