Objective: To assess the survival benefit of additional resection of an intraoperative positive proximal bile duct margin (BD_Marg) in patients undergoing hepatectomy for hilar cholangiocarcinoma (HCCA). Summary Background Data: Intraoperative evidence of invasive cancer at the proximal BD_Marg is associated with a dismal survival irrespective of whether a final negative BD_Marg is achieved with an additional resection. Methods: Clinicopathologic, operative, and survival data of consecutive patients undergone curative intent hepatectomy with bile duct resection (n = 75) for HCC (1989–2010) were analyzed. Results: Frozen-section examination of the proximal BD_Marg revealed invasive cancer in 19 of the 67 patients. After additional resection, which was possible in 18 cases, a secondary R0 BD_Marg resection was achieved in 15 patients (83.3%), with 2 of these having, at final pathology, positive radial and distal margins. Eventually, 8 patients were classified as R1 and 67 as R0 (54 primary R0 and 13 secondary R0). Median survival of patients who had a secondary R0 resection (30.6 months) was similar to that of primarily R0-resected patients (29.3 months) and significantly better than that of R1 patients (14.9 months) (P = 0.026). Median time to recurrence and site of recurrence were similar in R0 patients independently of the performance of an additional resection. The incidence of biliary fistula was significantly increased (44.4% vs 17.5%; P = 0.02) in patients necessitating a margin re-resection. Conclusions: Additional resection of a positive proximal BD_Marg, albeit associated with an increased risk of biliary fistula, offers a significant survival benefit and should be attempted whenever possible.