['To test, in AIDS patients, a previously proposed hypothesis of clonal population structure in Leishmania infantum, the agent of visceral leishmaniasis.', 'Forty-three stocks of L. infantum isolated from AIDS patients in Spain were analysed by multilocus enzyme electrophoresis.', 'The results were analysed in terms of population genetics according to previously described statistical methods. Departures from panmixia were examined by linkage disequilibrium analysis.', 'As previously shown in HIV-negative patients, classical manifestations of clonality were shown, namely strong linkage disequilibrium, over-representation of genotypes and overall lack of genotype diversity. The same dominant clonal genotype (MON1) was recorded in both HIV-positive and HIV-negative patients. Frequency of this dominant genotype was not statistically different in HIV-positive and HIV-negative patients.'] Is leishmania infantum clonal in AIDS patients too : epidemiological implications?