Sertoli cell cultures were obtained from isolated seminiferous tubules of adult crab-eating macaques (Macaca fascicularis). Cells were identified by their morphological characteristics and their capacity to produce and release in the culture medium 17β-estradiol and androgen-binding protein (ABP). Several cells were undergoing mitosis. Karyological analysis showed both diploid and tetraploid metaphases. Patterns of nuclear scission were also observed.