Pancreatic cancer is essentially a disease caused by inherited and acquired mutations in cancer-causing genes. A number of the genes responsible for the aggregation of pancreatic cancer in families have been discovered, including BRCA2, p16/CDKN2A, STK11 and PRSS1. Individuals can be tested for germline mutations in these genes; however, until recently, little could be done about the risk of pancreatic cancer if a patient was found to carry a mutation. Currently, new approaches are being developed to screen at-risk individuals for curable precancerous pancreatic lesions and laboratory studies have led to novel therapies that specifically target some of these genetic defects. This review focuses on the genetic basis for the familial aggregation of pancreatic cancer, with emphasis placed on the implications of the genetic alterations on clinical patient care.