Model calculations show that the oceans do not represent a global sink for chlorofluoromethanes (CFM 11 and 12) of any significance. The amount absorbed by the oceans consists essentially of three portions: The portion dissolved in the mixing layer; the one that enters the deep sea and the portion which is decomposed or disappears otherwise within the mixing layer by chemical or biological processes. The calculations show that the total amount of CFM which may have entered the oceans up to the present time cannot have exceeded a few percent even if high destruction rates would occur in the oceans. Solubility data in ocean water in conjunction with concentration data in the oceans indicate, however, that the net destruction rate of CFM 11 in the oceans is only of the order of 10-7 sec-1 .