Proton activation analysis was used for the determination of cadmium and lead in three sediment reference materials. The method is based on the 111'112Cd(p, xn)lllIn and the 2~176176 xn)2~ reactions. 111In and 2~were chemically separated by anion exchange. The results obtained were taken into account for the certification of the materials and are in the excellent agreement with the certified values.