Positional and Theoretical Astronomy Russian We present our results of comparisons of the XC1 catalogue with data from some modern catalogues of stars and extragalactic sources. Significant systematic errors in the XC1 positions and proper motions are not found. The external proper motion errors for stars fainter than 15^m are estimated to be 3—5 mas/yr depending on magnitude.proper motions of stars,positions of stars, systematic errors of catalogs