Abstract: In this paper a radiochemical separation procedure has been set up. Os and Ru of 10- 9 level in geological and environmental samples were distilled with KMnO4, collected in Na2S + NaOH solution and co-precipitated with CuS. In this procedure Rb, Sc, Hf, Ca, Ta, Fe, Cr, Co, Ir, Pt, Sb and Se have no interference. The chemical yields of Os and Ru were more than 90% and 95%, respectively. It is effective for determining Os and Ru in geological and environmental samples.