The rate constant for the reaction of the hydroxyl radical with 1,1,1-trichloroacetaldehyde has been determined at 298 ± 2 K. Rate data were obtained at atmospheric pressure by a relative rate method. The rate constant was also measured at lower pressures (1-3.4 Torr) using the discharge flow technique with OH radical detection both by resonance fluorescence and electron paramagnetic resonance. The results provide a value of k(OH + CCl₃CHO) = (1.1 ± 0.2) × 10^-12 cm³ molecule^-1 s^-1 at room temperature giving an atmospheric lifetime for CCl₃CHO with respect to reaction with OH radicals of 290 h.