Multilocus enzyme electrophoresis was performed on 76 European strains of Candida dubliniensis. Ten of the 20 enzyme-encoding loci were polymorphic, giving rise to 10 electrophoretic types within the sample studied. Investigation of the population genetics of a subset of 36 strains from HIV-infected patients in London showed the existence of strong heterozygote deficits and excesses associated with significant linkage disequilibria between pairs of loci. These findings, together with the predominance of multilocus genotypes, strongly suggest that C. dubliniensis is mainly (if not totally) clonal. Analysis of genotypes of a larger number of strains should confirm this conclusion and improve our understanding of the epidemiology of this pathogen.