The gas-phase reaction of OH radicals with toluene and toluene-d(8) and reactions of the resulting OH adducts with O-2 were studied in N-2/O-2 mixtures at atmospheric pressure and room temperature. OH production was performed by pulsed 248 nm photolysis of H2O2. Cw UV-laser long-path absorption at 308 nm was used for time-resolved detection of OH and OH-toluene adducts. The reaction OH + toluene was studied in Nz and O-2 and similar rate constants of (5.70 +/- 0.19) x 10(-12) cm(3) s(-1) (N-2) and (5.60 +/- 0.14) x 10(-12) cm(3) s(-1) (O-2) were obtained at 100 kPa. For toluene-d(8) the corresponding rate constants are (5.34 +/- 0.33) x 10(-12) cm(3) s(-1) (N-2) and (5.47 +/- 0.14) x sadsad (O-2) Absorption cross-sections of (1.1 +/- 0.2) x 10(-17) cm? were determined for both the OH-toluene and OH-toluene-d(8) adduct at 308 nm. Rate constants of (4.7 +/- 1.4) x 10(-11) cm(3) s(-1) and (1.8 +/- 0.5) x 10(-10) cm(3) s(-1) were determined for the OH-toluene adduct self-reaction and the OH-toluene adduct + HO2 reaction, respectively. Upper limits less than or equal to8 x 10(-15) cm(3) s(-1) were estimated for any reactions of the OH-toluene adduct with H2O2 or toluene. Adduct kinetics in the presence of O-2 is consistent with reversible formation of peroxy radicals with an estimated rate constant of (3 +/- 2) x 10(-15) cm(3) s(-1) and an equilibrium constant of (3.25 +/- 0.33) x 10(-19) cm(3) (toluene-d(8): (3.1 +/- 1.2) x 10(-19) cm(3)). The effective adduct loss from the equilibrium can be explained by (i) an additional, irreversible reaction of the adduct with O-2 with a rate constant of (6.0 +/- 0.5) x 10(-16) cm(3) s(-1) (toluene-d(8): (4.7 +/- 1.2) x 10(-16) cm(3) s(-1)), or (ii) a unimolecular reaction of the peroxy radical, with a rate constant of (1.85 +/- 0.15) x 10(3) s(-1) (toluene-d(8): (1.5 +/- 0.4) x 10(3) s(-1)). Consequences for the atmospheric degradation of toluene will be discussed.