Various studies highlight a gap on reliable methods to measure the quality of projects and environments in terms of Universal Design (UD) and Design for All (DfA). In particular, healthcare facilities need decision support systems to improve the well-being of as many users as possible through a systematic approach. The present research proposes an evaluation tool to support designers and decision makers in the adoption of UD to develop healthcare facilities suitable for a wide range of users. Several methodologies have been adopted: an in-depth literature review on the current state of knowledge on UD evaluation, workshops and focus groups with both users and experts, and the analysis of four hospital case studies. The result was an evaluation framework built by using a Multi-criteria Analysis (MCA) methodology. The first version of the tool was applied to an American hospital and validated d in an Italian pilot case study. The research outlines a tool called Design for All A.U.D.I.T., able to evaluate Physical, Sensory-cognitive, and Social qualities based on a hierarchical framework with criteria and indicators based on UD and DfA. The framework evaluates the different areas of the hospital from outdoor to indoor spaces, allowing hospital administrators to act to improve the well-being of users according to the critical aspects of UD identified by the tool. The analysis provides a report of the facility status and design strategies to support designers for new projects or buildings renovations. The application shows that DfA A.U.D.I.T. can assess hospitals by examining both spatial qualities and DfA criteria. The tool could represent a decision support system in the national and international context, where many hospitals are not newly built. Further research will include application in different facilities and building typologies, aided by the flexible structure of the tool, which allows measurement of the environment’s quality in terms of DfA and UD.