The pathogenicity and mortality rate of Candida albicans from various sites of the baboon were studied in mice. Tissue population and pathogenicity of four selected isolates of this group were compared to two isolates of human origin. Ninety-one percent and 100% of mice were found to be infected by use of the intraperitoneal and intravenous routes respectively. No significant variations were found among the strains of baboon and human origin. The kidney was found to be the most susceptible organ, followed by the brain. The greatest total count of C. albicans from kidney tissue occurred in 96 hours and from other organs in 6–24 hours. A hypothesis relating to kidney susceptibility to C. albicans infection was introduced.