The gas phase reactions of the NO3 radical, a ubiquitous constituent of nighttime atmospheres, with the reduced sulfur compounds COS, CS2 CH3SH, C2H5SH and CH3SSCH3 have been investigated. Using a relative rate technique and long path length Fourier transform infrared (FT-IR) absorption spectroscopy, rate constants for these reactions have been determined at 297¿2K in one atmosphere of air. The resulting rate constants (in units of 10-13 cm3 molecule-1 s-1) are: COS, <0.0004; CS2, <0.008; CH3SH, 10¿3; C2H5SH, 12¿3; and CH3SSCH3, 0.42¿0.09. A number of products from these reactions were determined using FT-IR absorption spectroscopy and combined gas chromatography/mass spectrometry. Atmospheric implications of these kinetic and product data are discussed.