The question of whether sea-spray droplets make a significant contribution to the transfer of heat and water vapor between the air and sea has been addressed by many researchers over the last few decades. Quantification of the effect is difficult owing to a number of factors; in particular, the available data on droplet concentrations over the sea are limited and the airflow over rough seas is not well known. In the work described in this paper, a model for simulating droplet trajectories over the sea was developed, taking into account the droplet evaporation and the effects of turbulence on the motion. This model was used to simulate the behavior of droplets under conditions for which field data on droplet concentrations were available, and the rates at which droplets are generated were calculated. Estimates of the spray contribution to the heat and mass transfer made using these results suggest that droplets are likely to make only a small contribution to the overall fluxes, except under storm conditions, when they could be a major source of water vapor. ¿ 1999 American Geophysical Union