Our research group has a long-term project supported by the Government of the Canary Islands to conduct the ecological monitoring of the three Marine Protected Areas (MPA) of the archipelago: ‘Isla de La Graciosa e Islotes del Norte de Lanzarote MPA’, ‘La Restinga – Mar de Las Calmas MPA’ (El Hierro Island) and ‘Isla de La Palma MPA’. This ecological monitoring is conducted on a yearly basis since 1994 and it records the abundance and diversity of macroalgae, invertebrates and fish population inside and outside the MPAs. During this period we have recorded a significant increse in the abundance and biomass of economically important species inside the MPAs compared to non-protected sites. Our results add to the growing body of literature that has shown that MPAs are very successful tools to preserve marine ecosystems.