NHC-catalyzed direct amidation of aldehydes with nitroso compounds is a powerful method for the synthesis of N-arylhydroxamic acids. A variety of aryl, alkyl, alkenyl, and heterocyclic aldehydes were found to give excellent yields of the corresponding N-arylhydroxamic acids. This chemistry was also extended to the synthesis of chiral N-arylhydroxamic acids by kinetic resolution of alpha-branched aldehydes, a domino amidation-redox amination reaction of acrolein, and a three-component reaction for the synthesis of N-arylaziridines.