Yttrium iron garnet (YIG) (Y3Fe5O12) films have been grown on single-crystal lithium niobate (LiNbO3) ferroelectric substrates by ion beam sputter deposition. X-ray diffraction, electron microscopy, magnetic measurement, and spin wave propagation results for the Y3Fe5O12 films suggest that they can be used in devices for mutual conversion of magnetic and electrical quantities.