In this paper, the quasiperfect cascade of separation elements with three withdrawals, which can separate a multicomponent mixture into three parts in one act of the separation, is presented. The developed scheme of cascade provides the increase of capacity of the isotope separation and, conse- quently, the decrease of the cost of isotopic products. The new scheme of the separating cascade is destined for nuclear, medical industries and etc. It can be used for the separation of isotopes selected from the multicomponent mixture, for task solution on the enrichment of different stable and radioactive isotopes and also for the getting of uncommon and expensive isotopes, which are needed for nuclear medicine and etc.