Chronic kidney disease (CKD) is a significant public health problem: every year the number of Americans living with CKD and requiring renal replacement therapy increases. In addition, individuals with CKD have substantially increased morbidity and mortality compared to the general population. The Longitudinal Chronic Kidney Dialysis (LCKD) Study is a multicenter, prospective, observational study of patients with moderate to severe CKD that was designed to better describe the course of the disease and the determinants of patient outcomes. Patients with moderate to severe CKD (glomerular filtration rate [GFR] < 60 ml/min/m2) from four academic nephrology clinics were enrolled between 2000 and 2002. Special cardiac and vascular testing has recently commenced as phase II of this study. Areas that have been or are currently being studied include anemia management, health-related quality of life (HRQOL), medication use, and markers of cardiovascular disease. This article describes the LCKD Study in the context of current knowledge of CKD.