Project Summary/Abstract Lung transplant (LTx) is an option for treating end-stage lung disease in cystic fibrosis (CF). Median survival after LTx for adults with CF has increased to 10 years, yet many patients with CF die from respiratory failure without considering LTx as a treatment option. A long-term objective of this research is to improve the care of individuals with CF through empowering patients for shared decision making about LTx. The proposed research is pilot testing an innovative decision support tool that incorporates information CF patients need to make informed decisions about LTx. We will utilize validated outcome measures, including the Preparation for Decision Making Scale and the Decisional Conflict Scale, to determine the preliminary efficacy of the web-based LTx decision support tool. The tool will be used for CF patients with a forced expiratory volume in one second (FEV1) less than 50% of predicted, individuals for whom the CF Foundation recommends annual discussion of LTx. These patients may be a decade or more away from LTx, but seek information about LTx as a potential treatment option in the future. Our research will also assess for differential use of the LTx decision support tool among CF patients with varied levels of socioeconomic status and health literacy by analyzing patient-level tool usage data with web analytics software, in order to optimize the tool for use among disadvantaged populations. Our LTx decision support tool incorporates up to date, CF-specific information about LTx and the proposed research is necessary to determine whether the tool changes meaningful outcomes for CF patients.