BACKGROUND AND OBJECTIVES: It is unclear if hemodiafiltration leads to a better quality of life compared with hemodialysis. It was, therefore, the aim of this study to assess the effect of hemodiafiltration on quality of life compared with hemodialysis in patients with ESRD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This study analyzed the data of 714 patients with a median follow-up of 2 years from the Convective Transport Study. The patients were enrolled between June of 2004 and December of 2009. The Convective Transport Study is a randomized controlled trial on the effect of online hemodiafiltration versus low-flux hemodialysis on all-cause mortality. Quality of life was assessed with the Kidney Disease Quality of Life-Short Form. This questionnaire provides data for a physical and mental composite score and describes kidney disease-specific quality of life in 12 domains. The domains have scales from 0 to 100. RESULTS: There were no significant differences in changes in health-related quality of life over time between patients treated with hemodialysis (n=358) or hemodiafiltration (n=356). The quality of life domain patient satisfaction declined over time in both dialysis modalities (hemodialysis: -2.5/yr, -3.4 to -1.5, P