Between March and May 2003, the leatherback turtle (Dermochelys coriacea) nesting population of the Pacuare Nature Reserve (northern Caribbean coast of Costa Rica) was surveyed for potential bacterial pathogens associated with the cloaca and upper respiratory tracts. A total of 189 isolates that belong to 15 genera, including 113 gram-negative and 76 gram-positive bacteria, were identified from samples of 70 nesting females. The majority of the bacterial species recovered in this study, including 5 Salmonella isolates, may be considered as potential pathogens for sea turtles, as well as for humans.