207 Background: Prostate cancer accounts for approximately 10% of cancer deaths in men worldwide. Clinical trials for metastatic castrate resistant prostate cancer (mCRPC) have established survival benefit with use of abiraterone (ABI) with prednisone or enzalutamide (ENZ). Despite their wide utilization, little is known about patient quality-of-life (QOL) outcomes for these agents. Our study evaluates patient reported QOL while taking ENZ or ABI/prednisone. Methods: 22 mCRPC patients were enrolled in an open label, nonrandomized manner to receive oral ENZ (n=12) or ABI/prednisone (n=6) per oncologist’s discretion. Patients completed multiple QOL validated questionnaires, including EPIC-26, FACT-P, and FACT-COG at baseline, 1,2,3,6,9 and 12 months or until progression/change of therapy. Surveys were scored by treatment group using mean, median, range, and standard deviations. QOL parameters were compared between the two groups with two-sided, two-sample T test and linear mixed models. Results: Surveys discontinued prior to 1 year secondary to disease progression/change of therapy were 58% and 33% for ENZ and ABI, respectively. By month 3, 50% of surveys were returned for ENZ and 33% for ABI. Month-to-month comparisons of QOL parameters including urinary irritation, incontinence, bowel, sexual, hormonal function, and overall well-being showed no significant differences between treatment groups or different rates of change. Perceived Cognitive Impairment was significantly lower for patients on ABI in month 3, yet Perceived Cognitive Ability favored ENZ in months 2 and 3. All other data points for cognition showed no significant differences. Conclusions: Data from FACT-COG shows discordance in perceived Cognitive Impairment and Abilities between ENZ and ABI in months 2-3. Other QOL domains indicated no difference between the two groups. The study was limited by a significant portion of patients with disease progression/change of therapy. For those on therapy, survey compliance remained high. Thus, the use of questionnaires is a feasible means of assessing patient outcomes and can be adapted to larger studies.