PROJECT SUMMARY While many questions remain regarding specific rates for HIV PEP preventable transmissions related to the real world challenges of HIV seroconversion and measuring risk, we do know that: 1) among individuals who experience a known exposure HIV PEP is effective and potentially cost saving if initiated in a timely manner and completed fully; 2) patients who have been offered, accepted, and even completed HIV PEP continue to report confusion and inaccurate information regarding its use; and 3) in many contexts decision aids have demonstrated improved patient knowledge regarding decision making, decreased decisional conflict, and improved patient-provider communication. Given these gaps, the long-term goal of this work is to develop, refine, and validate a technology-delivered patient-provider decision aid to assist providers in better understanding and effectively implementing HIV PEP in practice, and assist patients to better understand the decision they are making when provided with HIV PEP as an option so that they may more successfully 1) make the decision, and 2) complete the entire 28-day course of mediation when they decide to initiate HIV PEP. The proposed patient-provider decision aid leverages a known clinical opportunity to engage patients who are at risk for seroconversion in initiation of HIV PEP. By creating an internet-delivered multimedia tool that: 1) removes provider biases regarding what qualifies as an HIV risk from the discussion process; 2) slows the process of information sharing and decision making down and presents information in short, repeatable modules; and 3) incorporates an opportunity for patients to reflect on key priorities that have been shown to impact decision making and adherence (e.g. social support/stigma, HIV risk perception, cost/access, side effects) prior to making the decision we anticipate that patients will have less decisional conflict, feel more confident about their decision, and for patients who initiate HIV PEP, be more able to complete the entire 28- day regimen. Lastly, the proposal includes relationship building via a community advisory board to support all steps of the patient-provider decision aid development and subsequent testing. Principles of design justice (e.g. adopting co-design methods, developing specific mechanisms for accountability, centering the needs of marginalized users) will be used to partner with this group of patient and health care providers to design aspects of intervention content, and plan details of the future efficacy testing study.