The lack of consensus on how to evaluate surgical complications of donors in live donor liver transplantation (LDLT) and incoherence of cumulative data hampers efficient comparison of the outcome worldwide. We considered that the application of the internationally validated classification system introduced by Clavien in 2004 might be beneficial. Operative complications of 243 patients who underwent live donor hepatectomy for adult LDLT between January 1996 and October 2005 at the University of Tokyo were analyzed according to the system. Definitions for each grade in the system are: grade I, deviation from the normal postoperative course but without the need for therapy; grade II, complication requiring pharmacologic treatment; grade III, complication with the need for surgical, endoscopic or radiological intervention (IIIa/b: without/with the need for general anesthesia); grade IV, life-threatening complication requiring intensive care; grade V, death. Surgical morbidity was recognized in 67 donors (28%). No deaths occurred. The numbers of patients with complications were: grade I, 36 (15%); II, 10 (4%); IIIa, 12 (5%); IIIb, 9 (4%); IV, 0; V, 0. Six in IIIb underwent surgical repair for bile leakage. Clavien's system is simple and informative. It may serve as a common tool for the quality assessment in live liver donor surgery worldwide, and we propose its application whenever surgical complication of live donor is discussed.