We have examined the photochemical reactions occurring after irradiation at 200 nm of the aqueous nitrate ion, NO3-(aq). Using femtosecond transient absorption spectroscopy over the range 194-388 nm, we have characterized the formation and subsequent relaxation of the primary photoproducts of nitrate photolysis. The dominant photoproduct is the cis-isomer of peroxynitrite, which accounts for 48% of the excited state molecules initially produced. A slightly smaller fraction, 44%, of the excited molecules return to the electronic ground state of NO3- and relax to the vibrational ground state in 2 ps. The remaining 8% of the molecules initially excited react via the (NO)-N-. + O-.(2)- or the NO- + O-2 dissociation channels. Formation of NO2- and (NO2)-N-. is not observed, suggesting that the previous observations of these species in steady-state photolysis are caused by reactions occurring on a longer time scale.