The AGK3U is a updated version of the AGK3 catalog in which new positions from the Palomar "Quick V" survey have been added to improve the AGK3 proper motions. It provides FK4/B1950.0 positions and proper motions for 170,464 stars north of -2.5 degrees declination, at an average epoch of 1950.62. The proper motions have a two dimensional formal mean error of 0.82 arcsec/century. In addition to the positions and proper motions, the catalog contains the AGK3 number, the mean errors of the positions and proper motion in each coordinate, the photographic magnitude, the spectral type, and the Palomar plate position, epoch, and mean error.