After intravenous inoculation of mice with large doses of living Candida albicans, the kidneys are the only organs where multiplication of fungi occurs. After systemic challenge performed with varying doses of yeasts, kidney infection shows an identical pattern during the first 12 h, independently of the magnitude of the inoculum. Destruction of parasites occurs during the first 3 h and then C. albicans begins to multiply. Death occurs when the number of microorganisms in the kidneys exceed 10(5) viable units and the time of death is correlated with renal infection measured 12 h after challenge. An identical correlation is found when mice are pretreated with an immunosuppressor or immunostimulants. No statistical significance is observed in counts of C. albicans in right or left kidney, in males or females, but a slightly higher total count and a lower mean survival time are noted in female mice. These results show that counting C. albicans in kidneys 12 h after systemic infection provides a rapid screening test. In addition, this fact taken with the mortality may explain the nature of the pathological processes which occur during systemic candidiasis in mice.