Absolute rate coefficients for the reaction OH + CH₃CHO → products (1) were measured over the temperature range 201–348 K using the technique of pulsed laser photolytic generation of OH coupled to detection by pulsed laser induced fluorescence. The experiments were carried out at total pressures of 50 or 100 Torr (He or Ar bath gas). The accuracy of the rate constants obtained was enhanced by on-line optical absorption measurements of the acetaldehyde concentration. The temperature dependence of the rate coefficient, expressed in Arrhenius form, is given by k₁(201–348 K) = 4.38 × 10⁻¹² exp{(366 ± 40)/T} cm³ s⁻¹ with the rate coefficient at room temperature of 1.53 × 10⁻¹¹ cm³ s⁻¹. The estimated total error (95% confidence) associated with the rate coefficient derived from this expression is estimated as 5%, and is independent of temperature. The present results, which extend the database on this reaction to cover temperature relevant for the upper troposphere, are compared to previously published measurements, and values of k₁ for atmospheric modelling are recommended.