Changes in lipids and lipoprotein fractions were studied 6 months after a combined heart and liver transplantation in a patient with terminal ischemic heart disease due to homozygous familial hypercholesterolemia. The double transplant was followed by striking decreases in total and low-density-lipoprotein cholesterol levels (-71% and -79%) and content of apolipoprotein B in the low-density-lipoprotein fraction (-74%). There was also an increase in high-density-lipoprotein cholesterol (+7.8%). These changes are greater than those reported with portacaval shunt or plasma exchange. Liver transplantation may be considered in selected patients with homozygous familial hypercholesterolemia.