Abstract: Methods for the preparation of N-substituted hydroxylamine [B₁₂H₁₁NH₂OH]^– have been developed and optimized. The possibility of using two synthetic methods has been shown: (i) based on the hydroxylation of the deprotonated amino-closo-dodecaborate and (ii) the ipso-substitution of the iodonium substituent with free hydroxylamine. A theoretical study of the [B₁₂H₁₁NH₂OH]^– anion has been carried out by quantum-chemical calculations in the framework of density functional theory in order to determine its main structural characteristics.