Following the introduction of the Third Sector Code (regarding the voluntary sector), the theme of assessment of the social impact generated by non-profit organizations (NPOs) has re-emerged strongly, emphasizing the importance of adopting methodologies of measurement such as SROI ( social return on investment) .#An analysis conducted to assess the ability of the Association of Italian Volunteer Blood Donors (AVIS) to generate social value for blood donors and volunteers has highlighted the potential and limits of such processes, as well as of the specific methodology adopted. Among the critical factors are the risk that the survey may be interpreted as a mere formal task and the difficulties inherent in data collection. At the same time, this approach may stimulate a rethinking and reorientation of organizational strategies and managerial practices, improve communication and reporting of the incremental contribution generated through the activities put into place, and reinforce the relationships with those who contribute financial resources to the NPO.