Abstract: The present invention provides a pharmaceutical composition containing gossypol and phenformin, capable of exhibiting a synergistic effect in the treatment of pancreatic cancer. When gossypol and phenformin are mixed in a concentration range provided in the present invention and the mixture is applied to the treatment of pancreatic cancer, apoptotic effects on pancreatic cancer are remarkably increased because of the co-administration thereof even in a concentration range in which a significant pancreatic cancer treatment effect cannot be achieved by the administration of gossypol or phenformin alone, such that pancreatic cancer can be effectively treated. Additionally, when an anti-cancer agent is mixed in addition to gossypol and phenformin and the mixture is applied to the treatment of pancreatic cancer, apoptotic effects on cancer cells can be remarkably increased such that pancreatic cancer can be effectively treated.