Chronic kidney disease (CKD) is now a recognized global public health problem. It is highly prevalent and strongly associated with hypertension and cardiovascular disease (CVD); far more patients with a glomerular filtration rate below 60 ml min(-1) per 1.73 m(2) will die from cardiovascular causes than progress to end-stage renal disease. A better understanding of the complex mechanisms underlying the development of CVD among CKD patients is required if we are to begin devising therapy to prevent or reverse this process. Observational studies of CVD in CKD are difficult to interpret because renal impairment is almost always accompanied by confounding factors. These include the underlying disease process itself (for example, diabetes mellitus and systemic vasculitis) and the complications of CKD, such as hypertension, anaemia and inflammation. Kidney donors provide an ideal opportunity to study healthy subjects without manifest vascular disease who experience an acute change from having normal to modestly impaired renal function at the time of uninephrectomy. Prospectively examining the cardiovascular consequences of uninephrectomy using donors as a model of CKD may provide useful insight into the pathophysiology of CVD in CKD and, therefore, into how the CVD risk associated with renal impairment might eventually be reduced.