Twenty coral formations were evaluated in the area of Santa Marta in terms of: 1) composition and abundance of the principal substrate categories and 2) prevalence of coral diseases and bleaching. To obtain the information, bands of 10 x 1 m and 10 x 2 m were used, respectively. A total of 33 species of hard corals were registered. Algae and corals were the components with major cover, nonetheless, averages varied widely in the study area (coral= 4.0 ± 0.9 %-62.0 ± 7.2 %; algae = 30.6 ± 11.0 %-78.3 ± 3.0 %). The coral species with the highest averages cover were Colpophyllia natans, Diploria strigosa, Acropora palmata, and Montastraea cavernosa (7.5 ± 2.7 %, 6.7 ± 2.1 %, 4.0 ± 2.8 %, and 3.8 ± 1.0 %, respectively). Prevalence of coral diseases and bleaching were lower than 4 %. The reefs with the highest coral covers were associated to the Parque Nacional Natural Tayrona (Gayraca, Aguja, Chengue and Neguanje), whereas the lowest values were found near the urban centers (Santa Marta and El Rodadero). Even though there are some coral reefs showing relatively good conditions in the area of Santa Marta, the widespread trend is that algae are the predominant component of reef substratum.