Quantum yields, Φ, of OH and HO₂ in the ultraviolet photolysis of HO₂NO₂ (peroxynitric acid, PNA) at 193 and 248 nm and that of NO₃ at 193, 248 and 308 nm are reported. Quantum yields were measured using pulsed excimer laser photolysis combined with pulsed laser induced fluorescence (PLIF) detection of OH radicals and cavity ring-down (CRD) detection of NO₃ radicals. HO₂ radicals were quantified by converting them to OH via the HO₂ + NO → OH + NO₂ reaction and detecting OH. The quantum yields obtained at 296 K are: Φ_{193 nm}(OH) = 0.21 ± 0.12, Φ_{248 nm}(OH) = 0.085 ± 0.08, Φ_{193 nm}(HO₂) = 0.56 ± 0.09, Φ_{248 nm}(HO₂) = 0.89 ± 0.26, Φ_{193 nm}(NO₃) = 0.35 ± 0.09, Φ_{248 nm}(NO₃) = 0.08 ± 0.04 and Φ_{308 nm}(NO₃) = 0.05 ± 0.02. The quoted uncertainties are 2σ (95% confidence level) and include estimated systematic errors. Our results are compared with the previous quantum yield measurements of OH (MacLeod et al., J. Geophys. Res., 1988, 93, 3813) and NO₂ (Roehl et al., 2001, J. Phys. Chem., 105, 1592) at 248 nm and the discrepancies are discussed. The rate coefficients at 298 K for reactions of OH with HO₂NO₂, H₂O₂, HNO₃ and NO are also reported.