Sequential two photon photolysis of CS2 is discussed. Experiments in our lab and others have shown that photolysis of CS2 and O2 mixtures with light of energies below the SC-S bond dissociation energy produces OCS and SO2. We explain these results by the two photon sequential absorption and subsequent dissociation of CS2 to CS+S. The implications of this mechanism for the oxidation of CS2 in the atmosphere are discussed. Comparison to the currently accepted OH-initiated oxidation mechanism suggests that the sequential two-photon mechanism is too slow to be important in the atmosphere. ¿ American Geophysical Union 1995.