Abstract Data from the Voyager UVS solar occultation experiment are analyzed to determine the distribution of hydrocarbons in the upper atmosphere of Neptune. Objective inversion techniques are used to infer densities from the transmission properties of the atmosphere measured by the UVS. Densities of H 2 , CH 4 , and C 2 H 6 are determined over limited altitude ranges and constraints are placed on the abundances of C 2 H 2 and C 2 H 4 . The inferred densities when used in conjunction with models for the transport of CH 4 and C 2 H 6 imply that the CH 4 mole fraction in the stratosphere is between 6 × 10 -4 and 5 × 10 -3 , i.e., more than one order of magnitude larger than expected if the tropopause cold trap is operating. This conclusion is independent of assumptions about the temperature profile in the stratosphere. C 2 H 6 is produced from CH 4 photolysis with an efficiency of 30-50%. The eddy diffusion coefficient has a value of 1.0 ± 0.3 × 10 5 cm 2 sec -1 at and below 300 km, rising exponentially to a value of 2.4 +0.7 -0.5 × 10 6 cm 2 sec -1 at 550 km. The C 2 H 6 densities determined from this study are consistent with results from groundbased and Voyager infrared observations. The H 2 densities are in excellent agreement with results from the Voyager radio occultation.