Background: The survival benefit of chemotherapy compared to best supportive care (BSC) after percutaneous transhepatic biliary drainage (PTBD) was evaluated in patients with pancreatic or biliary tract cancer. Patients and Methods: A retrospective registry study was conducted at a tertiary-level university hospital. The endpoint was survival measured from the PTBD and the initiation of chemotherapy. Results: Among 158 patients (mean age=74 years, range=43-93 years; 51.9% women), 82 (51.9%) had pancreatic cancer and 76 (48.1%) had biliary tract cancer. After PTBD, 32 (20.3%) patients received chemotherapy and had a median survival of 11.7 months; 126 (79.7%) patients received only BSC resulting in a median survival of 1.7 months. The hazard ratio for survival at 1 year for patients who received chemotherapy compared to BSC was 0.22 (95% confidence interval=0.12-0.41, p<0.001). Conclusion: After PTBD, patients with pancreatic or biliary tract cancer should be critically evaluated by an oncologist to determine whether chemotherapy is possible, as it seems to significantly improve survival compared to BSC.