PURPOSE: To define the criteria for resection and/or radiation therapy (RT) of extrahepatic bile duct cancer. MATERIALS AND METHODS: Of 81 patients with extrahepatic bile duct cancer treated from 1983 to 1992, those with proximal duct lesions (n = 56) underwent RT and/or resection or palliative care, and those with distal lesions (n = 25) underwent resection with or without RT. Follow-up was available 3-114 months (median, 28 months). RESULTS: Patients with distal bile duct cancer lived longer than patients with proximal bile duct cancer (survival with Kaplan-Meier analysis, 53% vs 13% at 5 years, respectively, P < .01). Median survival in patients with proximal cancer after RT was more than double that without RT (17 months vs 6 months, respectively, regardless of stage [P = .01]); survival was not significantly different after resection. In patients with distal cancer, RT after resection made no significant difference in median survival (68 months). CONCLUSION: Patients with proximal cancer should undergo primary RT, and expectations should be limited. Patients with distal cancer should undergo resection, and RT may not be needed.