Recent observations have suggested substantial emission of sulfur compounds by oceanic water which could explain the presence of SO2 and SO+4 in the air above these waters. The emission is thought to increase with the productivity of the oceanic zones. This point is discussed in relation to the Gulf of Guinea, a zone of high productivity. During the first two campaigns between Dakar, Abidjan, and the Gulf of Guinea SO+4 concentrations were measured in the air. Between Abidjan and the Gulf of Guinea the atmospheric SO=4 concentrations decreased from 800 to 400 ng m-3. During the third campaign, between Abidjan and the South Equatorial Current (latitude 1¿S), the H2S and SO2 concentrations were measured. The mean H2S concentration was 20 ng m-3, and that of SO2 varied between 120 and under 50 ng m-3. The origins of SO2 and SO+4 in the air of this area are discussed through the daily variations of the H2S content of the air and a contribution from the forested zones of West Africa.