The TOBUS (a decision-making tool for selecting office building upgrading solutions) methodology and software have been developed as a result of a 2-year European research project, involving eight European institutions, in the frame of the JOULE III programme of the European Commission (EC), Directorate General XII, A structured diagnosis scheme enables architects and engineers to simultaneously handle the entire complex process of office building refurbishment or retrofit with respect to deterioration, functional obsolescence of building services, energy consumption and indoor environmental quality, The software tool can then be used to define the most appropriate and cost-effective actions, to elaborate consistent refurbishment scenarios and calculate a reasonable investment budget in the early stages of a refurbishment project. This paper provides an overview of the work performed in TOBUS and an overview of the methodology and final deliverables of the project.