Seawater samples collected at four stations in the Gulf of Maine, three on the Scotian Shelf, and at a singel station in the Sargasso Sea (Sept.-Oct., 1977) were analyzed for CCl3F-content using a rapid gas chromatographic technique carried out on board ship. The concentrations observed in the Gulf-average 2.9¿10-12 moles/liter, corresponding to significant supersaturation with regard to the overlying atmospheric concentrations and surface temperatures. Not all the excess can be attributed to prior equilibration at the colder temperatures prevailing at higher latitudes, and it seems likely that waste disposal activities may contribute to the local excess. Lower concentrations are observed at stations on the Scotian Shelf and in the Sargasso Sea, with observed stratifications in the CCl3F concentrations being well-correlated with previously described oceanographic features.