Abstract: Objective To evaluate the capacity load and nutritional status of elderly and non-elderly maintenance hemodialysis (MHD) patients, and to uncover the related risk factors leading to their fluid overload and malnutrition status. Methods 101 MHD patients were selected and divided into two groups by age:non-elderly group<65 years old (n=51) and the elderly group ≥ 65 years old (n=50). The body composition monitor (BCM), laboratory indicators and malnutrition-inflammation score (MIS) were used to evaluate the fluid load and nutritional status of the two groups, and the related risk factors probably causing fluid overload and malnutrition were analyzed. Logistic regression equation was used to analyze the independent risk factors of fluid overload and malnutrition. Results Compared with non-elderly MHD patients, the elderly patients had lower albumin (P=0.006), prealbumin (P<0.01) and body cell mass (P=0.03), and weaker grip strength (P<0.05). The ECW/TBW (P<0.01) and the incidence of malnutrition (P=0.004) were significantly higher in the elderly group than in non-elderly group. In MHD patients, ECW/TBW and MIS scores were positively correlated with age (P<0.01), while grip strength (P<0.01) and body cell mass (P<0.01) were negatively correlated with age. Single factor analysis showed that age (P<0.01), grip strength (P<0.01) and body cell mass (P<0.01) were correlated with ECW/TBW. Age (P=0.001), gender (P=0.010), albumin (P=0.01), prealbumin (P<0.01), grip strength (P<0.01) and body cell mass (P=0.003) were related to MIS score. The multivariate analyses results indicated that the decrease of body cell mass (P=0.001) was an independent risk factor for increasing ECW/TBW, suggesting body cell mass was an independent risk factor for fluid overload, and prealbumin (P=0.029) was an independent risk factor for malnutrition in MHD patients. Conclusions Compared with non-elderly MHD patients, fluid overload and malnutrition are more common in elderly MHD patients. Body cell mass is an independent risk factors for body fluid overload in MHD patients, while the prealbumin is an independent risk factor for malnutrition in MHD patients. Therefore, body cell mass assessed by BCM may be a clinically effective method to assess the capacity load status of elderly MHD patients. Clinical application of BCM combined with laboratory indicators can monitor the human body composition and nutritional status of MHD patients in real time.