To preserve proper growth of the planet, industries have to increase sustainability of produced good according to the compliance and governance regulations for NPD (new product development). Sustainability concerns economical, environmental and social aspects; among these issues, the last theme is the less argued in literature and this paper focuses on the social life cycle assessment of products. One of the crucial aspects of S-LCA, is the definition of impact categories and involved stakeholders. This work, proposes a new S-LCA methodology, according to UNEP/SETAC framework. After the clarification of stakeholders, categories and general notions already known on S-LCA, a test case is shown where the new approach is implemented. In this use case, stakeholders from an Italian product line are analysed, then categories of attribution of social impacts are outlined. The paper offers a step-by-step procedure useful to verify the S-LCA theories currently available on a practical industrial case, defining also weaknesses that might be addressed in future studies.