An artificial reef complex was built on the southern coast of Gran Canaria Island (Canary Islands), with the financial support of the Archipelago Autonomous Government. This artificial reef is composed of five separated units, each of them with different types of modular concrete blocks. Between November 1990 and March 1991, before the deposition of the concrete blocks, an oceanographic and biological assessment of the selected area was carried out which included oceanographic and SCUBA sampling at the artificial reef site, the coastal rocky bottom and a nearby sublittoral natural reef. The results obtained allowed us to make a bionomical chart of that coast and to characterize the entire area as oligotrophic, in the oceanographic and biological sense. Nutrient concentrations were low. Benthic communities were composed of different species of green algae and few live invertebrates were observed. The ichthyofauna was diverse, but with a low biomass.