OBJECTIVE, The purpose of this study was to evaluate accuracy for determining the total and lobar liver volumes using a multidetector CT scanner in potential donors undergoing living adult right lobe liver transplantation. SUBJECTS AND METHODS. Fifty-two adult donors underwent CT using a multidetector scanner after IV injection of 180 mt of contrast material. For volumetric determination, portal venous phase images were acquired at 60 sec. Hand-tracing was used to isolate the entire liver. and a curved hepatectomy plane was then identified in a manner simulating the surgical incision. Two observers performed hand-tracing of the entire liver to calculate total liver volume, and of the right lobe to calculate expected graft volume. RESULTS. The mean Volume of the entire liver, right lobe, and left lobe was 1807 mt, 990 mt, and 817 mt, respectively, for observer 1, and 1788 mt. 1007 mt, and 781 mt, respectively, for observer 2. There was significant agreement between the two observers in determining total and lobar liver volumes (r = 0.996, 0.977, and 0.965 for total, right lobe, and left lobe volumes, respectively: p < 0.0001). There was no statistically significant difference between the two observers in measuring total or lobar liver volumes (p < 0.0001). There was significant agreement between right lobe volume measured by each observer and graft weight obtained in 14 donors at surgery (r = 0.898 and 0.879, for observers 1 and 2, respectively; p < 0.001). CONCLUSION. Total and lobar volume determinations after virtual right hemihepatectomy provides accurate and reproducible information that is critical in selecting potential living liver donors.