The extraction of strontium and yttrium by a 0.2 M solution of dicyclohexano-18-crown-6 (DCH18C6) in n-octanol from nitric acid solutions as well as from solutions of yttrium nitrate in nitric acid was studied. Increasing the nitric acid concentration within the 0.1-7 M range and yttrium nitrate concentration within the 0.1-2 M range considerably improves strontium extraction, increasing its distribution ratio up to 40. Meanwhile, the yttrium distribution ratio at these conditions does not exceed 0.05. High separation efficiency of strontium and yttrium at a high yttrium nitrate concentration allows considering DCH18C6 as a promising extractant for the process of n.c.a. 89 Sr isolation from fast neutron irradiated yttrium targets.