The fluorescence of carbon disulfide vapor was measured as a function of both wavelength of excitation and wavelength of fluorescence. It was found necessary to invoke a vibrational cascade model in order to account for the observations. Vibrational deactivation occurred on every collision, whereas electronic deactivation was found to require about ten collisions.The quenching by the foreign gases Ar, N2, O2, CO2, COS, SF6, and C3H8 of CS2 fluorescence excited by a wavelength of 320.0 nm was measured and the rate constants computed. The degree of efficiency could be correlated with the complexity of the molecule as determined by its polarizability.