The role of cell-mediated immunity (CMI) in the protection against experimental murine candidiasis was studied. CMI-deficient animals prepared by adult thymectomy and treatment with antimouse thymocyte serum along with controls were challenged with one LD 50 (6.6 × 10 4) dose of Candida albicans. The course of infection in these animals was studied by mortality pattern, delayed type hypersensitivity reaction (DTH) to candida antigen, antibody formation, and viable count of organisms in kidney, spleen and liver at different time intervals. The T-cell-deficient animals were found to be highly susceptible to infection with C. albicans. A correlation was observed in the appearance of DTH and protection.