Objective: The purpose of this study was to compare the Health-Related Quality of Life (HRQOL) status of patients with end stage renal disease (ESRD) on hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) treatment, and to define in which way their perception of quality of life (QOL) is affected by socio-demographic characteristics, disease-related variables and laboratory findings. Material and Methods: In this cross-sectional study, 22 consecutive patients on CAPD treatment at a Training and Research Hospital (42%) and 30 consecutive patients on HD treatment at a private healthcare center (57%)-who met the eligilibity criteria- were evaluated in a period of three months between November 2004 and January 2005. The patients answered to two questionnaires with a face to face interview method. The first questionnaire was composed of questions regarding socio-demographic and disease-related variables. The second questionnaire was the Turkish version of The Medical Outcomes Study Short- Form 36 (SF-36) Health Status Survey, which was used to assess the general HRQOL. Data regarding laboratory findings and complications of chronic renal failure were collected from the patients' medical records. Results: CAPD patients had better physical functioning (p=0.003) and physical role limitation (p=0.001) scores in certain SF-36 sub-domains compared to HD patients. There was a moderate positive correlation between albumin levels and physical function, while thrombocyte counts were negatively correlated with vitality and social function in HD patients. In the CAPD group, calcium and hematocrit levels were positively correlated with vitality. There was a negative correlation between phosphorus levels and mental health status and a negative correlation between potassium levels and general health status of CAPD patients. Conclusion: In our study we observed higher quality of life scores in the CAPD group compared to the HD group especially in the area of physical function which may be explained by portability, easy application and mobility of these patients, which are some of the advantages compared to HD patients. Since QOL scores are affected by the modality of dialysis in ESRD patients, besides clinical parameters QOL status of these patients should also be considered in choosing the treatment modality and follow-up process.