INTRODUCTION: Cancer center websites are trusted sources of internet information about treatment options for prostate cancer. The quality of information on these websites is unknown. The objective of this study was to evaluate the quality of information on cancer center websites addressing prostate cancer treatment options, outcomes, and toxicity. MATERIALS AND METHODS: We evaluated the websites of all National Cancer Institute-designated cancer centers to determine if sufficient information was provided to address eleven decision-specific knowledge questions from the validated Early Prostate Cancer Treatment Decision Quality Instrument. We recorded the number of questions addressed, the number of clicks to reach the prostate cancer-specific webpage, evaluation time, and Spanish and mobile accessibility. Correlation between evaluation time and questions addressed were calculated using the Pearson coefficient. RESULTS: Sixty-three websites were reviewed. Eighty percent had a prostate cancer-specific webpage reached in a median of three clicks. The average evaluation time was 6.5 minutes. Information was available in Spanish on 24% of sites and 59% were mobile friendly. Websites provided sufficient information to address, on average, 19% of questions. No website addressed all questions. Evaluation time correlated with the number of questions addressed (R(2) = 0.42, p < 0.001). CONCLUSIONS: Cancer center websites provide insufficient information for men with localized prostate cancer due to a lack of information about and direct comparison of specific treatment outcomes and toxicities. Information is also less accessible in Spanish and on mobile devices. These data can be used to improve the quality and accessibility of prostate cancer treatment information on cancer center websites.