[en] A new separation scheme is presented for the neutron-activation analysis of selenium, osmium and ruthenium in solid samples such as rocks, sediments and biological materials. A neutron-irradiated sample accompanying the carriers of the three elements was heated with the bromide-SPA reagent to 250⁰C, whereupon selenium came out as gaseous selenium tetrabromide. The second distillation was performed by heating the residual sample with Ce(IV)-SPA reagent till 285⁰C to separate osmium as osmium tetroxide gas. The last distillation of ruthenium as ruthenium tetroxide followed under heating the residue with the Cr(VI)-SPA reagent till 245⁰C. Each distillate was absorbed in an appropriate absorbing solution from which selenium metal, osmium thiourea chromithiocyanato complex, and ruthenium metal were respectively recovered and they were submitted to γ-counting by means of a Ge(Li) detector coupled with a multi-channel pulse height analyzer. The chemical recoveries of the added carriers were found to be about 80% for selenium and above 90% for osmium and ruthenium. (auth.)