We report a reversible spin-reorientation transition between in-plane and out-of-plane orientation in Co0.35Pd0.65/Pd multilayer films, in situ measured with magneto-optical Kerr effects upon alternate depositions of the ultrathin CoPd and Pd layers. A misfit-strain modulation produced by the depositions of the alternating constituent layers might be one of promising candidates to controllably engineer spin orientations without applying an external magnetic field. (C) 2002 Elsevier Science B.V. All rights reserved.