Purpose: The purpose of this pilot study was to evaluate the Personal Patient Profile-Prostate (P4), a customized, Internet-based decision support system for men with localized prostate cancer. The goal of P4 is to assess influential personal factors, preferences for decisional control, information priorities and current symptoms; and then to provided customized output to assist the patient with decision-making during a clinical visit with a cancer specialist to discuss treatment options. Methods: A convenience sample of 30 men who sought consultation at the University of Washington Prostate Oncology Center used the program on a touch screen computer in a private patient education room. Participants answered validated questionnaires (including their personal factors) and were then presented with customized text and optional video clips intended to model how they might discuss their own preferences and priorities with their urologist. One month later, follow up questionnaires were mailed to all participants including the Decisional Conflict Scale and Preparation for Decision Making. Results: Twenty-eight (93%) men returned the one month questionnaire packet. Decisional conflict subscale means were as follow: factors contributing to uncertainty, 1.56 (SD=.58); perceived effective decision making 1.52 (SD=.56); and decisional uncertainty, 2.09 (SD=.99). The mean score for Preparation for Decision Making was 23.7 (SD=.63). There were no significant relationships between preparation score and any of the conflict subscales. Conclusion: These early results indicate that this approach for interactive multimedia computer-mediated decision making may result in men who are prepared for the difficult localized prostate cancer treatment decision and experience low decisional conflict. Men who reported higher decisional conflict were not less prepared and may have been conflicted related to other factors such as trait anxiety.