This study aims to examine and compare changes in quality of life after two common treatments for prostate cancer (PC), radical prostatectomy (RP) and radiation therapy (RT). Patients newly diagnosed with localized PC, scheduled to receive RP (n=68) or RT (n=66), completed three cancer/PC-specific psychometric instruments and three PC-specific utility instruments before treatment, and 2 and 12 months after treatment. We assessed the magnitude and time course of changes in psychometric and utility measures, and differences between treatments. The results showed that RP was associated with significant urinary and sexual dysfunction; RT caused bowel problems. Fatigue and pain were common to both. RP patients reported more problems with physical, role and social function. Utilities decreased significantly after both treatments. Effects were most severe 2 months post treatment, and then showed some recovery, but many endured for 1 year. After 1 year, 30-60% of patients had utility scores that were clinically significantly worse than at baseline. Secondary androgen deprivation therapy also significantly decreased psychometric and utility measures of quality of life. Many adverse symptoms reported 2 months after RP and RT endure for 1 year. Despite different symptom profiles, RP and RT result in similar utility decrements.