The effect of tin on the formation and temperature transformation of VO centers in Ge upon annealing has been investigated. It was found that the doping of Ge with tin leads to a change of reactions involving oxygen and vacancies and the new defect SnVO appears upon VO annealing. Doping Ge with tin gives rise to a considerable decrease in the formation efficiency of divacancies and VO centers and the latter exist in a very narrow temperatures range. VO2 complexes appear only upon annealing of SnVO centers. The assumption is made that the absorption bands situated at 718.9 and 733.6 cm-1 belong to the less stable configuration VO2* and the bands at 731.5 and 771.7 cm-1 correspond to stable configuration of VO2 centers.