It is observed that some venom may have an anticancer effect. Hemiscorpius lepturus is a most dangerous scorpion in Iran. Heminecrolysin is the most toxic fraction of Hemiscorpius lepturus venom and it is responsible for hemolytic effects of the venom. In this research, we purified heminecrolysin by FPLC, and HPLC methods and used MTT assay in prostatic cancer cell line (PC-3 cells). We observed that H.lepturus venom and its fraction (heminecrolysin) had anticancer effects on prostatic cancer cell line (PC-3) and inhibited cell growth.