Ecclesiastical properties - assets intended to serve the mission of the Church - are widely redundant in Italy. Buildings originally designed to host active religious communities have, in some cases, become empty or underused; in others, they have been successfully transformed through socially oriented adaptive reuse, emerging as places of solidarity and everyday life. This contribution examines a set of case studies involving the social reuse of ecclesiastical properties. The analysis focuses on the relationships between the new users and the owning ecclesiastical bodies, as well as on the motivations, expectations and governance arrangements that shape these processes. Strengths and weaknesses are assessed in relation to environmental, social, ecclesial, legal (both civil and canonical), economic and architectural sustainability. The study seeks to identify the factors that facilitate or hinder the social reuse of church property and to explore the conditions under which such initiatives prove sustainable over time.