A multicopper oxidase gene from the human pathogenic yeast Candida albicans was isolated and characterized. An open reading frame of 1872 bp, designated CaFET3, was identified, encoding a predicted protein of 624 amino acids and a molecular mass of 70.5 kDa. The identity between the deduced amino acid sequences of CaFET3 and the Saccharomyces cerevisiae FET3 gene is 55%. CaFET3 was localized on chromosome 6. A null mutant (fet3delta/fet3delta) was constructed by sequential gene disruption. Unlike the C. albicans SC5314 wild-type strain the fet3delta mutant was unable to grow in low-iron medium. The lack of growth of a S. cerevisiae fet3delta mutant in iron-limited medium was compensated by transformation with CaFET3. The null mutant strain showed no change in pathogenicity compared with the wild-type strain in the mouse model of systemic candidiasis.