Improving the energy efficiency of existing buildings through retrofitting interventions is essential to reduce energy consumption and mitigate climate change impacts. However, implementing effective retrofit strategies requires a deep and comprehensive analysis of the existing residential building stock. Our research work focuses on the Italian Public Residential Building stock (PRB) built between 1950 and 1980. During this historical period, attention to energy performance was not a priority, resulting in low thermal efficiency. Building on previous efforts such as the TABULA and EPISCOPE projects, which provided a taxonomy of harmonized European residential typologies, this study aims to develop a detailed and refined typological analysis specific to the public residential building sector in Italy. The methodology involves an extensive literature review to create a comprehensive database incorporating parameters such as building geometry, construction materials, energy systems and climate conditions. This database allows the identification and definition of distinct PRB typologies based on planimetric configurations, volumetric characteristics and aggregation patterns. This typological taxonomy will serve as a basis for the future implementation of a “retrofit intervention matrix” to assess the cost-effectiveness of various retrofit strategies in different typologies.