Two hundred and forty six aerosol samples collected in the Atlantic, Pacific and other ocean regions were analyzed for their mineral and sea salt aerosol content. The geometric mean mineral aerosol concentrations over most oceans were low; 0.36 μg m-3 in the central and northern North Atlantic, 0.35 μg m-3 in the Pacific between 30¿ N and 40¿ S, and 0.69 μg m-3 in the South Atlantic north of 40¿ S. The highest mean concentration, 14.2 μg m-3, was obtained in the tropical North Atlantic. High mineral aerosol concentrations were also obtained in the Mediterranean (4.29 μg m-3) and the Indian Ocean (4.76 μg m-3). Thus, arid regions appear to be the principal source of mineral aerosol in the marine atmosphere. In contrast, the sea salt aerosol concentrations are relatively constant from one region to the other with geometric means ranging from 3.34 μg m-3 to 8.71 μg m-3.