Abstract: We have performed simulation of reactions of nitroso- and nitrosocompounds with sulfur oxides by means of UB3Lyp/6-31g+(d) method. Gaussian 03w was used as basic programm.QST2 and QST3 methods implemented in Gaussian 03 w programm were used to find transition states for the reactions. We have proved that nitroso oxides are produced in the course of the reactions. The energetically preferable reactions procede in the triple state. The energy parameters were determined for every reaction involved. the realibility of the transitional state obtained were confirmed by both presence of the only one imaginary frequency for the structure and by IRC procedure.