An upper limit for the gas phase absorption cross sections for H2SO4 over the wavelength range 195 to 330 nm has been determined. Absorption measurements were made using a diode array spectrometer and a 100 cm long heated absorption cell. Gas phase H2SO4 was generated in a gas flow by titrating (equilibrating) known amounts of SO3 via the reaction SO3+H2O↔H2SO4 at elevated temperatures, ~500 K. Upper limits to the H2SO4 absorption cross sections were obtained, <1¿10-21 cm2 molecule-1, and provide an upper limit to the atmospheric photolysis rate of H2SO4. The implications of this cross section limit to stratospheric sulfur chemistry are discussed. ¿ 2000 American Geophysical Union