This illustrated manual is a guide to the distribution and identification of the 6 genera and 28 species of benthic and planktonic Chaetognatha known to occur in the Caribbean Sea, the Gulf of Mexico, the Florida Straits, and the southwestern North Atlantic Ocean. As background, previous studies of chaetognaths in these areas are reviewed, gross morphology of the different forms is described, and instructions on methods of preserving and handling specimens preparatory to identification are provided. The key to genera and species is preceeded by a discussion of chaetognath taxonomy. A description of each species, consisting of an abbreviated synonymy, a summary of taxonomically important morphological features, and horizontal and vertical distribution follows the key. The occurrence of species in relation to water masses in the Caribbean and adjacent areas is noted.