Mannose-binding lectin (MBL), a liver-derived C-type serum lectin, activates the complement cascade through the lectin pathway. Since the complement system contributes to the host defense against infections and mediates inflammatory processes including atherosclerosis, and since chronic renal failure (CRF) patients are prone to the development of infectious complications and cardiovascular disease, we focused on serum MBL levels in CRF patients who were either uremic, or who were receiving hemodialysis treatment.