The electroplating technique is used for producing thin sheets of copper- or nickel-based composites containing different volume fractions of alpha-alumina dispersions. The microhardness and tensile behaviour of such composites, in both the as-deposited and the annealed state, are characterized. The strengthening mechanism of electroplated composites is found to be a combination of Orowan-type strengthening and the Hall-Petch effect.