1. Hardened steel ShKh15 contains a comparatively large amount of residual austenite which decomposes within a fairly large temperature range. There are two regions of high stability of austenite, and between them there is an interval of its instability. 2. Formation of cementite begins at comparatively low (for chromium steels) tempering temperatures (250°C). The most intense formation of cementite begins above 350°C, and the range of carbide tranformations is larger than with carbon steels. 3. The obtained data can be used in the examination of transformations occurring in the working subsurface layers of rolling-contact bearings of steel ShHKh15 in operation, and also in the solution of problems of ensuring stability of quality, increased wear resistance, reliability, and service life of rolling-contact bearings.