Abstract The toxic and hormonal effects of polychlorinated biphenyls (PCBs) on testicular germ cell development were revealed with a germ-Sertoli cell co-culture model from embryonic chickens. Testicular cells were dispersed from 18-day-old embryo and exposed to Aroclor 1254 (A1254) alone and combined with α-tocopherol, flutamide and tamoxifen for discretion of the toxic and hormonal actions of A1254. Cell damage was evaluated by determinations of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) reduction and lactate dehydrogenase (LDH) leakage. Results showed that 10 μg/ml A1254 induced condensed nuclear and vacuolated cytoplasm; cell exfoliated and broke into pieces as a sign of cell degeneration after treatment for 6 h. The morphological cytotoxicity was confirmed by MTT reduction and LDH leakage assays. α-Tocopherol attenuated the toxic effect of A1254. After culture for 48 h, A1254 (0.1–1 μg/ml) manifested obvious hormonal effect to induce germ cell proliferation, while 10 μg/ml A1254 displayed obvious toxic and hormonal effects on germ and somatic cells. Blocking of either androgen receptor by flutamide or estrogen receptor by tamoxifen inhibited hormonal effect of A1254 on germ cell proliferation and increased the cytotoxicity. The above results indicated that A1254 exposure imposed both toxic and hormonal effects on embryonic testicular germ cell proliferation, which may cause reproductive disorder and even infertility at adulthood.