Rate coefficients for the gas-phase reaction CH3CO + O-3 -> products (1) were measured between 248 and 403 K at 60-200 Torr (N-2). Rate coefficients were measured under pseudo-first-order conditions in CH3CO with CH3CO produced by 248 nm pulsed laser photolysis of acetone and monitored using cavity ring-down spectroscopy at 532 nm. Rate coefficients were found to be pressure independent with a weak negative temperature dependence k(1)(T) = 1.50(-0.30)(+0.25) x 10 (11) exp[(300 +/- 50)/T] cm(3) molecule(-1) s(-1) and k(1)(296 K) = (4.4 +/- 0.5) x 10 (11) cm(3) molecule (1) s (1) where the quoted uncertainties are 2 sigma and include estimated systematic errors. Published by Elsevier B.V.