Abstract: The aim of this study was to discuss the role of mitochondria mediated apoptosis pathway in Sertoli-germ cell apoptosis induced by manganese in cocks. Cock Sertoli-germ cells were cultivated in the DMEM for 24 h added with MnCl2, whose final concentrations were 0, 2, 3, and 4 mmol·L^-1 respectively. The apoptosis was detected by AO/EB double staining. Mitochondrial transmembrane potential was detected by flow cytometer. Expression of Cytochrome c (Cytc) in cytolymph was detected by western blotting. The activities of Caspase-9, 3 were examined by spectrophotography. Compared with control group, the apoptosis index (AI) of cock Sertoli-germ cells was significantly increased (P＜0.01), mitochondrial transmembrane potential was significantly decreased (P＜0.01), expression of Cytc in cytolymph was increased, and the activity of Caspase-9, 3 were increased (P＜0.01) in 2, 3, and 4 mmol·L^-1 MnCl₂ group. The apoptosis mediated by mitochondria pathway was one of the reproductive toxic mechanisms caused by manganese.