The positions of about 306,000 common stars of the recently published catalogs ACRS and PPM are compared. The positions agree very well (rms < 0″.1) at the epoch of 1950, but the differences become larger as the epoch becomes farther from 1950 due to the deficiency in the accuracy of proper motions. The rms at the epoch of 2000 is about 0″.36. The agreement is better for the stars in the southern hemisphere, as is shown in the figures below, although the southern part of PPM (1991 April version) is still preliminary.