Fourier transform infrared (FTIR) smog chamber techniques were used to investigate the atmospheric chemistry of the isotopologues of methane. Relative rate measurements were performed to determine the kinetics of the reaction of the isotopologues of methane with OH radicals in cm ³ molecule ⁻¹ s ⁻¹ units: k(CH ₃ D + OH) = (5.19 ± 0.90) × 10 ⁻¹⁵ , k(CH ₂ D ₂ + OH) = (4.11 ± 0.74) × 10 ⁻¹⁵ , k(CHD ₃ + OH) = (2.14 ± 0.43) × 10 ⁻¹⁵ , and k(CD ₄ + OH) = (1.17 ± 0.19) × 10 ⁻¹⁵ in 700 Torr of air diluent at 296 ± 2 K. Using the determined OH rate coefficients, the atmospheric lifetimes for CH _{4– x} D _x (x = 1–4) were estimated to be 6.1, 7.7, 14.8, and 27.0 years, respectively. The results are discussed in relation to previous measurements of these rate coefficients.