In order to assess the importance of marine reserves on the population structure of groupers in the Western Mediterranean, abundance and size of Epinephelinae were recorded by visual censuses in six marine protected areas (MPAs): Carry-le- Rouet and Banyuls in France, Medes, Cabo de Palos, Cabrera and Tabarca in Spain.Four species of Epinephelinae were recorded, Epinephelus caninus (Valenciennes, 1843), E.costae (Steindachner, 1878), E. marginatus (Lowe, 1834) and Mycteroperca rubra (Bloch, 1793). The dusky grouper E. marginatus was by far the most abundant species. Significant negative gradients of abundance and biomass of groupers were observed in Cabo de Palos, Cabrera and Tabarca. Species richness and abundance of groupers were higher in the 3 southern MPAs.Eventually, a significant positive relationship was evidenced in all MPAs between grouper abundance and the abundance of other fishes. Therefore, grouper abundance could be viewed as an indicator which testified to the "good health" and stability of fish community, as advocated by Goeden (1982).