Several recent studies by others have demonstrated the preventive and therapeutic efficacy of scorpion venom in different animal tumor models and cell culture systems including prostate, breast, colon and skin cancers. Polypeptide extracted from the Egyptian scorpion venom (Leiurus quinquestriatus), is being studied for both prevention and treatment of prostate cancer. We proposed that there are alterations in pattern of cell cycle in prostate cancer cell line (PC3) post incubation with scorpion venom (1 mg/ml) for 24 h in vitro. The results are supported by comparing the percentage of cells in each phase of cell cycle It showed an increasing of apoptotic rate as 26.33% for pre G1; 71.2 % for G1/G0; 20.4% for S, and 8.4 % for G2/M phases, compared with cell control recording 66.4 % for G1/G0, 25.9% for S, and 7.7 % G2/M phases, respectively. Data recorded that scorpion venom induced Pre-G1 phase PC3 cell arrest for enhancing and providing the chance for the role DNA repair system. The present results providing strong rationale for further studies, to evaluate prevention and intervention strategies for L. quinquestriatus venom in pre-clinical prostate cancer models.