Background. Fibroblast growth factor-23 (FGF-23) is a phosphorus-regulating substance. Circulating FGF-23 levels increase markedly in dialysis patients and are independently associated with increased risk of mortality. Given the fact that cardiovascular disease is the leading cause of death in dialysis patients, the aim of this study was to test if elevated FGF-23 levels might be associated with left ventricular mass index (LVMI) and left ventricular index of myocardial performance (MPI) in maintenance haemodialysis patients.