Carbon disulfide (CS2) was determined in surface water and the overlying atmosphere during three cruises covering the coastal areas of the eastern United States, the temperate North Atlantic, and the Sargasso Sea (April/May, August, September 1986: 25¿--44 ¿N and 66¿--81 ¿W). The CS2 concentrations in surface waters were within the range of 2.5--510 pmol S(CS2) L-1 (picomol CS2-sulfur per liter). The mean concentrations in open ocean waters and coastal waters were 16¿8 (n=95) and 33¿19 pmol S(CS2) L-1 (n=110), respectively. Comparison of the CS2 concentrations measured in April/May and in September suggests the possibility of seasonal variability in the production of CS2 in surface waters. The distribution patterns of CS2 in the atmospheric boundary layer were similar to those observed in surface waters, with higher concentrations near the coast and lower levels over the open ocean. The typical background mixing ratio of CS2 in the remote marine boundary layer is of the order of a few parts per trillion by volume. On the basis of our measurements of CS2 in surface seawater and the overlying atmosphere, the global sea-to-air CS2 flux is estimated to be 6.8 (3.4--14) Gmol S(CS2) yr-1, equivalent to 0.22 (0.11--0.44) Tg S yr-1. ¿ American Geophysical Union 1987