Lipids may adversely affect renal function. The recently published MRC/BHF Heart Protection Study (HPS) subgroup analysis showed that simvastatin significantly reduced the fall in glomerular filtration rate in high-risk patients with and without diabetes mellitus. These findings are in line with those of smaller earlier studies, including the GREek Atorvastatin and Coronary heart disease Evaluation (GREACE) Study. Lipid lowering trials need to consider that changes in renal function may occur. Renal and ischaemic heart disease may progress in parallel and statins may be beneficial to both organs.