The trophic structure of the nearshore fish communities of the southwestern Gulf of Mexico was analyzed through application of the ECOPATH II model. Emphasis was on commercially exploited species of which sharks, mackerels, shrimps and crabs are the most important. The area considered corresponds to the region of the western gulf in which fishing activity is mostly developed. Most of the fish data used for the predator-prey matrix were taken from the literature, while invertebrate information was from specific studies conducted previously.