The present study sought to identify the therapeutic efficacy of adjuvant external beam radiotherapy (EBRT) for carcinomas of the extrahepatic bile duct (EHBD) and gallbladder. Twenty-one patients with pathologically verified EHBD carcinoma and 18 patients with gallbladder carcinoma were analyzed retrospectively by Cox regression analysis for predictors of survival. The overall 5-year survival rates after resection were 33%for EHBD carcinoma and 56%for gallbladder carci noma. The overall 5-year survival rate for EHBD carcinoma was 60%in 8 patients without microscopic residual disease (RO), 15%in 9 patients with microscopic r esidual tumor (R1), and 0%in 4 patients with macroscopic residual tumor (R2). T he overall 5-year survival rate of gallbladder carcinoma patients was also decr eased with R status equal to 73%, 40%, and 0%for RO, R1 and R2, respectively. Adjuvant radiotherapy significantly improved the 5-year survival rate in 7 pat ients with R1 disease of EHBD carcinoma (P = .035), compared with survival in 2 patients who underwent resection alone. However, no significant difference was n oted in the 5-year survival rate between the resection plus EBRT group and the resection alone group for gallbladder carcinoma. Multivariate analysis revealed that histopathologic grade (G) was an independent predictor of survival for EHBD carcinoma and that direct invasion of liver parenchyma was a predictor of survi val for gallbladder carcinoma. This study suggests that curative resection provi des the best survival for patients with EHBD and gallbladder carcinoma, and that radiotherapy may play a beneficial role in controlling local-regional residual EHBD carcinoma tumors. However, new strategies for adjuvant therapy are needed to improve survival in patients with gallbladder carcinoma. The present study sought to identify the therapeutic efficacy of adjuvant external beam radiotherapy (EBRT) for carcinomas of the extrahepatic bile duct (EHBD) and gallbladder. Twenty-one patients with pathologically verified EHBD carcinoma and 18 patients with gallbladder carcinoma were analyzed retrospectively by Cox Regression analysis for predictors of survival. The overall 5-year survival rates after resection were 33%for EHBD carcinoma and 56%for gallbladder carci noma. The overall 5-year survival rate for EHBD carcinoma was 60%in 8 patients without microscopic residual disease (RO), 15%in 9 patients with microscopic r esidual tumor (R1), and 0%in 4 patients with macroscopic residual tumor (R2). T he overall 5-year survival rate of gallbladder carcinoma patients was also decr eased with R Status equal to 73%, 40%, and 0%for RO, R1 and R2, respectively. Adjuvant radiotherapy significantly improved the 5-year survival rate in 7 pat ients with R1 disease of EHBD carcinoma (P = .035) , compared with survival in 2 patients who underwent resection alone. However, no significant difference was n oted in the 5-year survival rate between the resection plus EBRT group and the resection alone group for gallbladder carcinoma. Multivariate analysis revealed that histopathologic grade (G ) was an independent predictor of survival for EHBD carcinoma and that direct invasion of liver parenchyma was a predictor of survi val for gallbladder carcinoma. This study suggests that curative resection provi des the best survival for patients with EHBD and gallbladder carcinoma, and that radiotherapy may In fact, new strategies for adjuvant therapy are needed to improve survival in patients with gallbladder carcinoma.