An Impact Assessment (IA) is a process aimed at structuring and supporting the development of policies. Besides the fact that IA assumes different features when applied to different sectors, really it should help policy makers in evaluating the contribution to the fisheries sustainability of new regulations. The recent improvements and development around the IA methodologies go more and more toward the concept of a Sustainability Impact Assessment (SIA). The evolution of IA in the fishery sector has followed the general and increasing need in having a more and more integrated type of analysis, focusing on the three dimensions of sustainability (environmental, economic and social). This paper synthesizes the methodology developed under the EU FP7 SOCIOEC project,1 whose main objective was the application of the most recent EU guidelines on IA to the current (and future) EU fishery management. The result is an integrated approach taking into account the main pillars of sustainability and a strong stakeholders’ involvement. A clear step-by-step procedure based on both qualitative and quantitative type of analyses has been defined, the last step being the “rating” phase, an essential step in a SIA, that provides the possibility to assess the results of different policy options (allowing policy makers to select the most appropriate one) in terms of acceptability, effectiveness, coherence and efficiency. The overall methodology has been tested on different EU regions, fisheries and management measures.