A non-sampling visual observation technique was used to measure solid-vapor equilibria of carbon dioxide in mixtures of light natural gas constituents. Frost points for the carbon dioxide + methane binary were determined for mixtures containing 1.00 %, 1.91 %, and 2.93 % moles of carbon dioxide at pressures ranging from (962.1 to 3008.2) kPa and temperatures ranging from (168.6 to 187.7) K. The addition of ethane and nitrogen to the carbon dioxide + methane binary system was also examined while keeping the carbon dioxide composition constant to determine the effect on the frost point.