PURPOSE: To study the effectiveness of the Patient Preferences for Prostate Cancer Care (PreProCare) intervention in improving the primary outcome of satisfaction with care and secondary outcomes of satisfaction with decision, decision regret, and treatment choice among patients with localized prostate cancer. METHODS: In this multicenter randomized controlled study, we randomly assigned patients with localized prostate cancer to the PreProCare intervention or usual care. Outcomes were satisfaction with care, satisfaction with decision, decision regret, and treatment choice. Assessments were performed at baseline and at 3, 6, 12, and 24 months, and were analyzed using repeated measures. We compared treatment choice across intervention groups by prostate cancer risk categories. RESULTS: Between January 2014 and March 2015, 743 patients with localized prostate cancer were recruited and randomly assigned to receive PreProCare (n = 372) or usual care (n = 371). For the general satisfaction subscale, improvement at 24 months from baseline was significantly different between groups (P < .001). For the intervention group, mean scores at 24 months improved by 0.44 (SE, 0.06; P < .001) from baseline. This improvement was 0.5 standard deviation, which was clinically significant. The proportion reporting satisfaction with decision and no regret increased over time and was higher for the intervention group, compared with the usual care group at 24 months (P < .05). Among low-risk patients, a higher proportion of the intervention group was receiving active surveillance, compared with the usual care group (P < .001). CONCLUSION: Our patient-centered PreProCare intervention improved satisfaction with care, satisfaction with decision, reduced regrets, and aligned treatment choice with risk category. The majority of our participants had a high income, with implications for generalizability. Additional studies can evaluate the effectiveness of PreProCare as a mechanism for improving clinical and patient-reported outcomes in different settings.