Arsenic is a toxic substance that spreads widely around the environment and accumulates as metalloid in the earth's crust. Arsenic and its derivatives are found in drinking water, nutrients, soil, and air. Exposure to arsenic is associated with lung, blood, skin cancer and various lesions. Curcumin is a polyphenolic compound derived from Curcuma longa (turmeric) rhizome and is one of the main curcuminoids. Curcumin is known to be antioxidant, antibacterial, anti-inflammatory, analgesic effects. This study aimed to investigate the potential of sodium arsenite to transform embryonic fibroblast cells and to evaluate the cytotoxic and genotoxic effects of curcumin in neoplastic transformed cells. Neoplastic cells transformation was induced by sodium arsenite in Balb/c 3T3 cells at the end of 32 days. After transformation assay, the transformed cells were treated with various concentration of curcumin to evaluate cell viability, lactate dehydrogenase activity and DNA damage for 24h. The results revealed that curcumin decreased cell viability and increased the activity of lactate dehydrogenase enzyme in neoplastic transformed Balb/c 3T3 cells. In conclusion, the results demonstrated that curcumin has an anticancer effect on neoplastic transformed Balb/c 3T3 cells by causing DNA damage.