Prostate cancer is a leading cause of death among the aging men. Surgical or radio therapy is effective when the cancer is confined to the prostate gland but once the cancer spreads beyond the pelvis, even chemotherapy and hormonal ablation therapy fails in curing this disease. Our previous studies have shown that β-glucan induces apoptosis in prostate cancer cells. Cellular viability of these cells treated with β-glucan was measured by MTT assay. β-glucan induced dose- and time-dependent inhibition of cell viability in LNCaP cancer cells. In flow cytometry analysis, β-glucan induced dose- and time-dependent apoptotic activities in LNCaP cancer cells. In addition, increased of expression caspase-3, caspase-9, Bax, and cytochrome C but decreased of expression Bcl-2 was observed in LNCaP cells treated with β-glucan. These results suggest that β-glucan induces apoptosis in LNCaP human prostate cancer cells mediated mainly through the increased of expression caspase-3, -9, Bax, cytochrome C and decreased of expression Bcl-2.