Temperature-dependent near-IR photodissociation spectra were obtained for several vibrational overtone transitions of peroxynitric acid (HNO4) with a tunable OPO photolysis/OH laser-induced-fluorescence system. Band-integrated photodissociation cross-sections (integralsigma(diss)), deter-mined relative to that for the 3nu(1) OH stretching overtone, were measured for three dissociative bands. Assuming unit quantum efficiency for photodissociation of 3nu(1) we find 2nu(1) + nu(3) (8242 cm(-1)) = (1.21 x 10(-20)) (independent of temperature), 2nu(1) (6900 cm(-1)) = 4.09 x 10(-1)8 * e((-826.5/T) (295 K > T > 224 K), and nu(1) + 2nu(3) (6252 cm(-1)) = 1.87 x 10(-19) * e((-1410.7/T)) (278 K > T > 240 K) cm(2) molecule(-1) cm(-1). The photodissociation cross-sections are independent of pressure over the range 2 to 40 Torr. Temperature-dependent quantum yields (0) for these transitions were obtained using integrated absorption cross-sections (integralsigma(abs)) of HNO4 overtone vibrations measured with a FTIR spectrometer. In the atmosphere, photodissociation in the infrared is dominated by excitation of the first over-tone of the OH stretching vibration (2(nu1)). Inclusion of all dissociative HNO4 overtone and combination transitions yields a daytime IR photolysis rate of approximately 1 x 10(-5) s(-1). This process significantly shortens the estimated lifetime of HNO4 in the upper troposphere and lower stratosphere.