Background/Aims: Studies comparing quality of life (QOL) between peritoneal and hemodialysis patients have yielded inconsistent results. Physical (PCS) and mental component summary (MCS) scales of Short Form 36 (SF-36) health survey are highly validated measures of self-assessed QOL. We sought to evaluate these indices in PD patients: (1) as measures of QOL, (2) predictors of QOL, (3) to study change in QOL over time, and (4) to compare QOL in PD vs. hemodialysis patients. Methods: SF-36 questionnaires were administered every 3 months to patients over a 2-year period and PCS and MCS were calculated. Mean follow-up was 15.3 ± 6.6 months for PD and 14.5 ± 5.7 months for HD. Results: Average PCS in PD (31.8 ± 7.8) was lower than HD (36.9 ± 9.8) (p < 0.02), while MCS was similar in the groups (p = NS). The prevalence of depression was 26.1% in PD and 25.4% in HD patients (p = NS). Serum albumin was the only significant predictor of PCS among PD patients and explained much of the decrease in PCS in them. The number of hospitalizations and in-hospital days were significantly lower for PD compared to HD patients (p < 0.05). PCS as well as MCS remained stable in both groups throughout the observation period. Conclusion: Self-assessed physical function is diminished, while mental function is similar in PD compared to HD patients. When corrected for serum albumin, this difference is eliminated. Over time, QOL in patients treated with PD remained stable.