Feeding habits of four fish species (Diplodus annularis, Scorpaena porcus,Scorpaena notata, and Serranus cabrilla) caught on the Loano artificial reef were studied to assess the role played by the reef in their diet. Samples were obtained either by spear fishing on the reef or by a trammel net in the surrounding area. Diet composition in terms of decapods and amphipods (constituting the main prey groups) was compared with the species composition within these taxa present on the reef and on surrounding bottoms sampled using various techniques (e.g. suction sampling and grabs). S. porcus and S. notata caught with trammel nets feed very little on reef species (only 5% and 6%, respectively, of individuals belonging to species common to stomach contents and the blocks). The specimens of S. notata and S. cabrilla, caught by spear fishing on the blocks forming the reef, prove to be more closely related to the artificial structures, with 58% and 78%, respectively, of individuals belonging to species common to both. D. annularis feeds on a wider spectrum of species that are almost all present on the reef blocks (91%). Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.