The role of systemic chemotherapy in advanced biliary tract cancer (BTC) is known to be very limited although various single-agent or combination therapies had been tested. However, there is a possibility that palliative chemotherapy induce prolong survival and improve quality of life in advanced BTC based on several studies. A GERCOR study showed the promising result of gemcitabine in combination with oxaliplatin as first line chemotherapy in advanced BTC. Therefore, this phase II trial was planned to investigate efficacy and toxicity of combination chemotherapy with gemcitabine and dose adjusted oxaliplatin in patients with inoperable BTC in Korea.