Atmospheric dimethylsulfide measurements made in marine air at Cape Grim, Tasmania, have been combined with a simple photochemical box model to provide estimates of monthly mean flux of dimenthylsulfide from the Southern Ocean upwind of Cape Grim. The flux estimates for midsummer agree remarkably well with the independent estimates made for the latitude of Cape Grim based on oceanic surface water data and simple sea-air transport models. However, for midwinter the flux estimates made here, based on atmospheric dimethlysulfide data, are as much as an order of magnitude lower than those made elsewhere based on oceanic surface water data. ¿ American Geophysical Union 1995.