In the era of living donor liver transplantation (LDLT), graft size is related to recipient prognosis. This study was performed to compare the clinical outcomes according to the graft-to-recipient weight ratio (GRWR) in adult LDLT. Seventy-nine adult patients who had undergone LDLT between June 1997 and June 2002 were retrospectively analyzed. The patients were divided into two groups according to the GRWR (group I, GRWR < 0.8%, n = 11; group II, GRWR > or = 0.8%, n = 68). The mean follow-up period was 19.4 (range 1 to 48) months. The recipients were 62 men (78.5%) and 17 women (21.5%) of mean age 45.2 (range 18 to 63) years. The overall patient survival rates were 74.7% at 1 year and 70.7% at 2 years. The patient survival rate in group I was 54.6% at 1 year and 40.9% at 2 years, whereas that in group II was 77.9% at 1 year and 75.3% at 2 years, showing a significant difference (P = .03). There were no significant differences in postoperative total bilirubin, transaminase enzyme level, prothrombin time (INR), portal vein flow on Doppler sonography, amount of ascites through the drain, complications, or acute rejection rates between the two groups. In conclusion, the minimum acceptable graft size in an adult-to-adult LDLT is GRWR of 0.8%. This study suggests that careful postoperative management and/or technical modifications during surgery are necessary, because small-for-size grafts (GRWR < 0.8%) result in lower patient survival rates.