Hyperlipidemia may be one of the risk factors in the development of atherosclerotic disease in renal transplant recipients. In the present study, 24 kidney recipients with hyperlipidemia were treated with an HMG-CoA reductase inhibitor, pravastatin (10 mg/day). All recipients had been treated with cyclosporine (CsA), azathioprine (Az), and prednisolone (Pred). The mean total cholesterol (T-chol) level decreased from 323 +/- 7.4 to 261 +/- 7.9 mg/dl at one month after starting treatment (P less than 0.01) and this level did not change during treatment for further 6 months. The mean LDL cholesterol level was also decreased from 205.9 +/- 11.2 to 118.7 +/- 8.1 mg/dl at 3 months after starting treatment (P less than 0.01). On the other hand, pravastatin did not affect the levels of HDL-cholesterol and triglycerides. Pravastatin did not show any effects on the white blood cell, monocyte, and lymphocyte counts, or the hemoglobin concentration (NS). One patient displayed a slight elevation of aspartate aminotransferase and alanine aminotransferase levels, but this was not sufficient to cease treatment. Pravastatin did not adversely affect the renal function or creatinine phosphokinase (CPK) levels. Two recipients developed nausea and vomiting and their treatment was stopped. Pravastatin appears to be a safe and efficacious method of treating hyperlipidemia in renal transplant recipients.