Deuterated oleates have been synthes/zed by semihydrogenation of acetylenic intermediates. [ll-2H~]Oleate was prepared by two-carbon chain extension of the C~6 alcohol obtained from [1-2l-I~]octyl bromide and 7-octyn-l-oL [8-2H2] and [7-=H2]oleates were both prepared from dimethyl suberate, tetradeutefo intermediate C~6 alcohols were synthesized from [1,8-2H4] and [2,7-2H4]octane diols by monobtomination, conversion to deuterated 9-decyn-l-ols and reaction with octyl bromide. Oxidation gave [8-2H2]-9-octadecynoate and [2,7-2H2]-9-octadecynoate, after semihydrogenation of the latter, deuterons at C-2 were removed by exchange with aqueous alkali. [6-2H2] and [5-2H2]oleates were obtained from methyl 5-tetradecynoate, semihydrogenation, deuterium exchange at C-2 and two malonate extensions gave [6-2H=]oleate; reduction with lithium aluminum deuteride, two malonate extensiom and semihydtogenation gave the [5-2H~] ester. [4-2I-I2] and [3-=H2]oleates were both obtained from methyl 7~is-hexadecenoate, exchange of the a protons and chain extension gave the [4-=H=] ester and reduction with lithium aluminum deuteride and chain extension gave the [3-2H=] ester. * NRCC No. 17794.