Marine Protected Areas (MPAs) are important tools to achieve both marine conservation and resources management objectives. The degree to which MPAs achieve such objectives is defined as management effectiveness and is strongly variable. A key factor that may affect MPAs management effectiveness is the management performance, defined as the level of effort exerted to enhance and sustain MPAs management. ‘Organization Science' (OS) is a discipline that investigates organizations and provides useful tools to analyze their management performance. MPAs, due to a number of intrinsic features, can be considered as organizations. The aim of the study is to investigate management performance of Mediterranean MPAs by employing ‘OS' approach. We collected data on 11 MPAs from France, Greece, Italy and Spain by interviewing managers and staff members. Several organizational variables have been investigated (e.g. existence of quantitative goals, the effort and strategy in carrying out activities coherent with goals, like environmental education and enforcement, time spent, people involved and efficacy assessment). Only five MPAs have from 9% to 69% explicit quantitative goals. The effort spent in carrying out the activities to support the stated goals is usually low. The study suggests there is room for further improving the management performance of Mediterranean MPAs. This could affect directly their MPAs effectiveness and represent an important step in the prospective of the 2020 CBD targets, calling for effectively managed MPAs.