The purpose of the project was to characterize the extent and magnitude of chemical contamination in southwest Puerto Rico, as part of a larger effort to link coral condition with chemical contamination. The study area extended from Guanica Bay west past the town of La Parguera. The Puerto Rico Planning Board has classified the terrestrial and marine environments of the study area as a Zone of Special Planning, and the Puerto Rico Department of Natural and Environmental Resources has designated the marine environment as a Natural Reserve. In May 2005, a reconnaissance mission resulted in the collection of 71 sediment samples that were used to characterize sediments in the study area in terms of total organic carbon (TOC). In August 2005, sediments were collected from 43 sites, randomly selected within the high and low TOC strata, using standard NSandT Program protocols, for contaminant analysis. A broad suite of chemical contaminants were analyzed in the sediment samples including polycyclic aromatic hydrocarbons (PAHs), chlorinated pesticides including DDT and its metabolites, polychlorinated biphenyls (PCBs), major and trace elements, butyltins, and polybrominated flame retardants (PBDEs). Coral tissues (mustard hill coral, Porites astreoides) were collected at eight sites and were analyzed for PAHs, chlorinated pesticides including DDT and its metabolites, PCBs, major and trace elements, and butyltins. Water samples were analyzed for total nitrogen and total phosphorus. This project provides valuable baseline data on sediment and coral tissue chemical contamination that is georeferenced and posted on the internet through the NOAA's National Status and Trends data portal.