Pancreatic cancer, the fourth most common cause of cancer deaths, has a five-year survival rate of 5% or less. Surgical removal of the tumor may improve survival, but survival remains poor even in optimally resected patients. The best adjuvant therapy for patients with resected pancreatic cancer is not clear. Surgical resection followed by chemoradiation and maintenance chemotherapy has been considered the most beneficial treatment for improving survival, but more recent studies have suggested that chemotherapy alone is more effective. The purpose of this article is to review randomized controlled studies of adjuvant chemoradiation or chemotherapy alone in the treatment of resected pancreatic cancer and to determine the optimal adjuvant therapy after curative resection with negative or microscopically positive margins. The outcomes of interest were overall survival and disease-free survival. The results indicate that chemoradiation is an acceptable option for adjuvant treatment. Three of the four randomized controlled trials suggest that adjuvant chemoradiation for resected pancreatic cancer improves overall survival. Adding gemcitabine to the chemoradiation regimen also confers increased disease-free survival. Providers counseling patients regarding treatment options for resected pancreatic cancer should continue to recommend adjuvant therapy—a combination of chemotherapy including gemcitabine and radiotherapy—for appropriately selected patients.