To find changes in activity of red-cell sodium-lithium counter transport (RBC Na+/Li+CT) in IgA nephropathology (IgAN) and renal hypertension (RHT), we measured the activity of RBC Na+/Li+CT in 21 patients with IgAN and 13 patients with RHT and compared it with that in 23 normal persons and 17 essential hypertension (EHT) patients by improved Canessa's method. RBC Na+/Li+CT activity in the EHT patients and EHT patients with positive family history was significantly higher than that in normal group. The activity of TBC Na+/Li+CT in the hyperlipidemic RHT patients was increased as compared with the normal group. The activity of RBC Na+/Li+CT in IgAN patients with hyperlipidemia and hyperlipidemic hypertensive IgAN patients was significantly higher than that in normal group. There was positive correlation between the activity of RBC Na+/Li+CT and serum cholesterol level in 34 patients with renal disease. The results indicate that enhanced activity of Na+/Li+ CT is a genetic marker for EHT patients, and hyperlipidemia is probably related to the enhanced activity of RBC Na+/Li+CT in parts of RHT patients and IgAN patients.