Continuing an investigation of the alkaloids from the epigeal part of the plant Nitraria komarovii Iljin et Lava gathered in May, 1987, by column chromatography of the benzene fraction of the total bases we have isolated a new base (I) with mp 243-244°C (ethanol-acetone), composition C₁₁H₁₂N₂O, [α]ᴰ ±0°. The mass spectrum, UV spectrum and IR spectrum of (I) were analyzed. Its molecular composition was 1 oxygen atom greater than that of deoxypeganine with similar mass-spectral fragmentations; the presence of (M - 16)⁺ and (M - 17)⁺ ions and ready solubility in water indicated its N-oxide nature. Reduction with zinc in hydrochloric acid gave deoxypeganine (II) identified by IR, NMR spectra and mixed melting point. PMR spectra of (I) and deoxypeganine showed downfield displacement of aliphatic and aromatic protons, confirming the base was deoxypeganine N-oxide at N-1. N-Oxides have not previously been found among quinazoline alkaloids, although their presence has been shown indirectly.