This paper discusses the magnetic and magneto-optical properties of Pt/Co multilayers, which we propose are an attractive candidate for a magneto-optical storage medium. Thin films, prepared by electron beam evaporation, have an easy axis of magnetization perpendicular to the film plane, a square magnetic hysteresis loop, and a coercivity of ∼1 kOe, when the individual Co layers are less than 4 A thick. The polar Kerr rotation, θK, is a modest 0.1–0.2° at 820 nm, but a large optical reflectivity is responsible for a good figure of merit. Further, θK for Pt/Co multilayers increases at shorter wavelengths, where higher storage densities are possible. Initial results of thermomagnetic writing on these layers are presented.