The resistance of outbred CD1 mice immunodepressed with cyclophosphamide to the systemic infection induced by the three species of Candida: C. albicans, C. krusei and C. viswanathii was studied. The administration of cyclophosphamide, three days before the challange of the Candida species causes a degree of immunodepression in relation to the dose of drug: decrease of leucocytes of the peripheral blood and decrease of the weight and of the cellularity of the spleens. The CD1 mice were immunodepressed with cyclophosphamide (150mg/Kg) three days before the intravenous challange with graded doses of cells of the three species of Candida. They are much more susceptible, compared to normal mice, to the systemic infection induced by C. albicans and also by C. viswanathii but in this case only when inoculated at the highest concentration. They are resistant, like normal mice, towards the C. krusei even in the case in which the degree of immunodepression of the animal is furtherly increased (with stronger doses of the drug). The number of colony forming units (CFU) from the kidneys of the immunodepressed mice with cyclophosphamide correlates the median survival times.