Diffusion coefficients of dichlorodifluoromethane in hydrogen, helium, nitrogen, and air were determined by means of reversed-flow inverse gas chromatography, at atmospheric pressure and temperatures in the region of 312.6-350.8 K. The uncertainty of the present values lies at their third decimal point. Comparing them with the respective values predicted by various empirical equations, it is concluded that relations utilizing diffusion volumes, such as Fuller-Schettler-Giddings, Gilliland, and Huang, resulted in better agreement: 1.8-2.7% in H-2, 0.3-0.8% in He, 2.5-3.3% in N-2, and 0.9-1.8% in air. The temperature exponents for CCl2F2's diffusion were as follows: 1.55, 1.58, 1.76, and 1.77 in H-2, He, N-2, and air, respectively, ranging between the values predicted by simple kinetic theory and semiempirical equations.