Arsenic trioxide (ATO) has been found to exert anti-cancer activity in various human malignancies. However,the molecular mechanisms by which ATO inhibits tumorigenesis are not fully elucidated. In the current study,we explored the molecular basis of ATO-mediated tumor growth inhibition in pancreatic cancer cells. We usedmultiple approaches such as MTT assay, wound healing assay, Transwell invasion assay, annexin V-FITC, cellcycle analysis, RT-PCR and Western blotting to achieve our goal. We found that ATO treatment effectivelycaused cell growth inhibition, suppressed clonogenic potential and induced G2-M cell cycle arrest and apoptosisin pancreatic cancer cells. Moreover, we observed a significant down-regulation of Skp2 after treatment withATO. Furthermore, we revealed that ATO regulated Skp2 downstream genes such as FOXO1 and p53. Thesefindings demonstrate that inhibition of Skp2 could be a novel strategy for the treatment of pancreatic cancer byATO.