Rate coefficients have been measured for the gas phase reactions of hydroxyl (OH) radicals and ozone with two unsaturated esters, allyl acetate (CH3C(O)OCH2CH=CH2) and isopropenyl acetate (CH3C(O)OC(CH3)=CH2) The OH experiments were carried out using the pulsed laser photolysis - laser induced fluorescence technique over the temperature range 243-372 K and the kinetic data used to derive the following Arrhenius expressions (in units of cm3 molecule-1 s-1): allyl acetate, k1 (2.33 ± 0.27) x 10-12 exp[(732 ± 34)/T]; and isopropenyl acetate, k2 (4.52 ± 0.62) x 10-12 exp[(809 ± 39)/T]. At 298 K, the rate coefficients obtained (in units of 10-12 cm3 molecule-1 s-1) are: k1 = (27.1 ± 3.0) and k2 (69.6 ± 9.4). The relative rate technique has been used to determine rate coefficients for the reaction of ozone with the acetates. Using methyl vinyl ketone as the reference compound and a value of 4.8 x 10-18 cm3 molecule-1 s-1 as the rate coefficient for its reaction with O3, the following rate coefficients were derived at 298 ± 4 K (in units of 10-18 cm3 molecule-1 s-1): allyl acetate, (2.4 ± 4.7) and isopropenyl acetate (0.7 ± 0.2). The results are discussed in terms of structure-activity relationships and used to derive atmospheric lifetimes for the acetates.