Bioelectrical impedance analysis (BIA) is a technique to evaluate body composition and nutritional status by measuring the small electrical current through human body. This technique has the advantages of relatively simple, speedy, and non-invasive. BIA measures the original values of extracellular water volume (ECW), intracellular water volume (ICW), phase angle (PhA), resistance (R), reactance (Xc) and impedance vector length, which can be used to evaluate volume status, nutritional status, protein energy wasting (PEW) status, muscle tissue analysis and adipose tissue analysis with clinical importance in dialysis patients. This article reviews BIA used in hemodialysis and peritoneal dialysis patients.