Jung Eun Lee,1,2 In Young Jo,3 Song Mi Lee,3 Woo Jeong Kim,3 Hoon Young Choi,2,4 Sung Kyu Ha,4 Hyung Jong Kim,5 Hyeong Cheon Park2,4 1Department of Internal Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, 2Severance Institute for Vascular and Metabolic Research, Yonsei University College of Medicine, 3Department of Nutrition Services, Gangnam Severance Hospital, 4Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, 5Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea Background: The number of elderly people on dialysis is increasing rapidly. Fluid overload and malnutrition status are serious problems in elderly dialysis patients. We aimed to compare the hydration and nutritional status through bioimpedance analysis (BIA) between young and elderly hemodialysis (HD) patients and to analyze risk factors related to fluid overload and malnutrition status in these patients.Method: We conducted a cross-sectional study, in which 82 HD (males 42, mean age 58.7±12.9 years) patients were enrolled. We collected different types of data: laboratory data, such as serum creatinine, albumin, total iron-binding capacity, hemoglobin, total cholesterol; anthropometric data, such as hand grip strength (HGS); BIA data, such as intracellular water, skeletal muscle mass, body cell mass, bone mineral content, phase angle (PhA), extra cellular water (ECW)/total body water (TBW) ratio; and malnutrition-inflammation score (MIS), which is a traditional nutritional parameter for dialysis patients. All patients were stratified into two groups according to their age: young (