A red-water bloom in Kingston Harbor, Jamaica, in October 1962 is described and discussed. The red water occurred during a brief period at the peak of a growth and decay cycle of a population of Exuviella sp. For several months before, during, and after the bloom, data on carbon fixation, chlorophyll, phytoplankton and nutrient concentrations were obtained at a station close to the bloom in Kingston Harbor and at another station in the Caribbean Sea.