To improve surgical results after resection of pancreatic cancer, clinical trials of postoperative adjuvant treatment have been aggressively performed worldwide. In the USA, postoperative chemoradiation therapy is supported on the basis of the results of the Gastrointestinal Tumor Study Group (GITSG) trial published in 1985. In Europe, chemotherapy was approved as postoperative adjuvant therapy based on the results of the European Study Group for Pancreatic Cancer-1 (ESPAC-1) trial published in 2004 and Charité Onkologie (CONKO)-001 study published in 2007. As in Europe, postoperative chemotherapy is recommended in Japan based on the results of the Japanese Study Group of Adjuvant Therapy for Pancreatic Cancer-02 (JSAP-02) trial published in 2009. In recent years, gemcitabine has been recognized as the first choice for adjuvant chemotherapy after surgery. Clinical trials with gemcitabine, fluorouracil, and molecular targeting agents are currently under way.