Recurrence of hepatitis C virus (HCV) after living donor liver transplantation was investigated using technetium-99m- diethylenetriaminepentaacetic acid-galactosyl human serum albumin (Tc-99m-GSA) liver scintigraphy. Four patients with decompensated cirrhosis due to HCV infection were retrospectively reviewed in this study. Scintigraphy was performed to determine the hepatic uptake ratio of the tracer corrected for disappearance from the blood, as well as the maximal removal rate of the tracer by hepatocytes, as parameters of hepatic functional reserve. In all patients, serum HCV ribonucleic acid (RNA) was detected 3 months after transplantation. The corrected hepatic uptake ratio and removal rate showed little change after transplantation in two patients without the recurrence of HCV infection. In another two patients, these levels were decreased at 3 months after transplantation. In one patient, recurrent HCV infection was diagnosed by confirmatory histologic examination at 12 months after transplantation. In the other patient, both levels declined further at 8 months. Although treatment was initiated with a combination of interferon plus ribavirin, this patient died of progressive hepatic failure. In conclusion, a decrease in scintigraphic parameters at 3 months after transplantation suggests recurrent HCV infection affecting the graft. Tc-99m-GSA liver scintigraphy is a useful noninvasive method for evaluating graft functional reserve.