Cel was filled in the upper part of a glass column (@ 3.0 x 30.0 cm) and 10 g of molecular sieve 5A and 10 g of diatomaceous earth Hyflo Super-Cel in the bottom part of a glass column.Two gram of the feed was dissolved in 200 ml of hexane and was run through the column resulting the adsorption of most of the methyl esters in a column as shown in Table 3. Then the column was eluted with 800 ml of chloroform at a flow rate of 0.26 ml/min. The contents and composition of methyl esters in each eluants were determined by the same method as described above.R e s u l t s Many runs have been made with the mixed ethyl esters from the Japanese sardine oil and mixed methyl esters from linseed oil with different temperatures, flow rates, kind of solvents, kind of molecular sieves, and sample sizes. Among them representative figures were shown in Tables 2 and 3.As seen from Table 2, the concentrated ethyl icosapentaenoate (conc.:84.5%) wasobtainedinyield of39.5 0h.Recovery of ethyl icosapentaenoate was 96.4%) and recovery of ethyl esters of sardine oil fatty acids was 97.50/0, whereas yield of concentrated methyl linolenate was 15.1 (conc.:> 90.Oo/o) from the mixed methyl esters of linseed oil fatty acids, yield of methyl linolenate was 85.6 "/I), and recovery of methyl esters of linseed oil fatty acids was 90.3 '%I ( Table 3 ) .From those results the molecular sieve column seems to be an effective tool for concentrating the ethyl icosapentaenoate in the mixed ethyl esters from sardine oil. L i t e r a t u r e I J.M.M.MorenoandJ. L . L . Ruk, GrasasyAceites22,351 [ l ! ) i l ] .