Abstract: Biochemical effects of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) on the sertoli cell culture from prepubertal male Wistar rats were examined by light and transmission electron microscopy. Sertoli cell culture was obtained by sequential collagenase and trypsin-EDTA treatment. TCDD was added to the cell culture at the concentration of 10, 100, 500, and 1000pg ml-1, respectively and control group was treated with saline. Distinct histopathological changes in the sertoli cell culture were noted after exposure to TCDD. At 2 days after treatment, the increase of degenerated sertoli cells were 11.8, 18.7, 28.4, and 30.8% at the concentration of 10, 100, 500, and 1000pg ml-1, respectively. Similarly, at 4 days, those increased as 16.5, 28.9, 35.7 and 48.9%, and at 6 days as 25.7, 38.4, 43.7, and 69.9%, respectively. They were significantly different from those in the control group (p<0.05). The maximum degenerative change of Sertoli cells was observed at the concentration of 1000pg ml-1 and at 6 days after treatment. The research finding suggested that TCDD showed a direct effect on sertoli cells in culture. A further study is needed to elucidate the mechanism of the action of TCDD on sertoli cells.