Objective: We performed a cross sectional study on the association between body composition and HRQOL in PD patients from Korean Cohort Study for Outcomes in Patients on Peritoneal Dialysis (KNOW-PD) in Seoul National University Hospital. Body composition was determined by bioimpedance spectroscopy. HRQOL was assessed by KDQOL-SF version 1.3 Questionnaire, which is summarized to three composite scores-kidney disease component summary score (KDCS), physical composite summary (PCS), mental composite summary (MCS). The relations between hydration status, lean tissue index (LTI), and fat tissue index (FTI) and HRQOL were analyzed by regression analysis. Methods: 196 PD patients were included in the present study. There was a significant difference in KDCS and PCS between groups determined by hydration status, but no difference in MCS. There was no significant difference in HRQOL between groups determined by LTI or FTI. KDCS, PCS, and MCS had a significant negative correlation with hydration status. PCS had a significant negative correlation with FTI. In subgroup analysis stratified with sex, dialysis vintage, residual renal function (RRF), co-morbidity score, and subjective global assessment (SGA), over hydration showed a negative relationship with HRQOL. FTI showed a negative relationship with HRQOL in male, PD duration > two years, lower RRF, higher co-morbidity and SGA. Results: Both hydration status and FTI were associated with HRQOL and increased hydration status negatively affected HRQOL in PD patients. Further longitudinal or intervention studies are needed to evaluate the impact on HRQOL of changes in body composition to ESKD patients. Conclusions: Objective: End stage kidney disease (ESKD) patients have poor health-related quality of life (HRQOL) compared to general population. Protein energy wasting and over-hydration, which are common in peritoneal dialysis (PD) patients, may affect changes in body composition. This study evaluated whether alterations in body fluid status or nutritional indices assessed by body composition monitor (BCM) may predict HRQOL from PD patients. Methods: We performed a cross sectional study on the association between body composition and HRQOL in PD patients from Korean Cohort Study for Outcomes in Patients on Peritoneal Dialysis (KNOW-PD) in Seoul National University Hospital. Body composition was determined by bioimpedance spectroscopy. HRQOL was assessed by KDQOL-SF version 1.3 Questionnaire, which is summarized to three composite scores-kidney disease component summary score (KDCS), physical composite summary (PCS), mental composite summary (MCS). The relations between hydration status, lean tissue index (LTI), and fat tissue index (FTI) and HRQOL were analyzed by regression analysis. Results: 196 PD patients were included in the present study. There was a significant difference in KDCS and PCS between groups determined by hydration status, but no difference in MCS. There was no significant difference in HRQOL between groups determined by LTI or FTI. KDCS, PCS, and MCS had a significant negative correlation with hydration status. PCS had a significant negative correlation with FTI. In subgroup analysis stratified with sex, dialysis vintage, residual renal function (RRF), co-morbidity score, and subjective global assessment (SGA), over hydration showed a negative relationship with HRQOL. FTI showed a negative relationship with HRQOL in male, PD duration > two years, lower RRF, higher co-morbidity and SGA. Conclusions: Both hydration status and FTI were associated with HRQOL and increased hydration status negatively affected HRQOL in PD patients. Further longitudinal or intervention studies are needed to evaluate the impact on HRQOL of changes in body composition to ESKD patients.