Observations are recorded on the time of spawning of 83 species of Caribbean reef fishes. Details of seasonal variations in the percentage of sexually active fishes are given for 35 species. The majority of species spawn mostly when water temperatures are minimal, in February, March and April. The expected biomass of reef fish eggs in the plankton is about twelve times greater in the above mentioned period than in the period from June to December. Normal recruitment to insular fisheries may be very greatly dependent upon the success of parent stocks spawning elsewhere in the Caribbean and the abundance of recruits to a particular area may be dependent upon the speed and direction of the prevailing currents which carry larvae and juveniles to the insular shelves.