Spectral dependences of the total absorption cross sections near the N K(ls) ionization threshold have been measured in transmission for the first time for solid-phase sodium nitrate NaNO₃ using synchrotron radiation of the Russian-German soft x-ray beamline at the electron storage ring BESSY-II. On the basis of these measurements, which were performed with correct consideration of the background and instrumental distortions, partial N K absorption cross sections and the oscillator strengths for the π and σ shape resonances were determined for NaNO₃.