Imaging of diffuse liver disease is traditionally done with Tc-99m-sulfur colloid. The advent of Tc-99m-labeled hepatobiliary agents led the authors to reevaluate the role of Tc-99m-sulfur colloid. A total of 95 paired Tc-99m-diethyl-IDA and Tc-99m-sulfur colloid studies were performed in 61 patients (60 paired studies in liver transplant patients and 35 paired studies patients who had not received liver transplants). The following parameters were visually graded on a five-point scale: Tc-99m-diethyl-IDA clearance and time of appearance of appearance of intestinal activity; and Tc-99m-sulfur colloid liver size, bone marrow activity, splenic size, splenic activity, lung activity. Total serum bilirubin levels were used as the standard measure of liver function. The Tc-99m-diethyl-IDA parameters correlated more highly with total serum bilirubin than did the Tc-99m-sulfur colloid parameters in both the transplant and nontransplant groups. In conclusion, Tc-99m-diethyl-IDA appears to be the preferred radiopharmaceutical for evaluation of hepatocellular function, although both agents may be needed in certain clinical situations.