A series of mixed Mn-Zr oxides with different molar ratios Mn/Zr (0.1-9) have been prepared by coprecipitation of manganese and zirconium nitrates and characterized by X-ray diffraction (XRD) and BET method. It has been found that at concentration of Mn below 30 at%, the samples are single-phase solid solutions (MnxZr1-xO2-δ) based on a ZrO2 structure. X-ray photoelectron spectroscopy (XPS) measurements showed that manganese in these solutions exists mainly in the Mn4+ state on the surface. An increase in the Mn content mostly leads to an increase in the number of Mn cations in the structure of solid solutions, however a part of manganese forms Mn2O3 and Mn3O4 in crystalline and amorphous states. The reduction of these oxides with hydrogen was studied by a temperature-programmed reduction technique, in situ XRD, and near ambient pressure XPS in a temperature range from 100 to 650 oC. It was shown that the reduction of the solid solutions MnxZr1-xO2-δ proceeds via two stages. During the first stage, between 100 and 500 oC, Mn cations incorporated into the solid solutions MnxZr1-xO2-δ undergo the partial reduction. During the second stage, at temperatures between 500 and 700 oC, Mn cations segregate on the surface of solid solution. In the samples with more than 30 at% Mn, the reduction of manganese oxide was observed: Mn2O3 → Mn3O4 → MnO.