The yeast Dipodascopsis uninucleata UOFS Y128 produces 3-hydroxy-5,8,11,14-eicosatetraenoic acid (3-HETE) and 3-hydroxy-5,8,11,14,17-eicosapentaenoic acid (3-HEPE) from arachidonic acid and eicosapentaenoic acid, respectively. The maximal yield of 3-HETE from arachidonic acid was 1.9% : this was achieved by (i) adding arachidonic acid after 46 h growth of a synchronised culture, this being the point at which sexual reproduction and the formation of asci was highest, (ii) using medium buffered to pH 7 in the absence of sucrose and (iii) a fatty acid concentration of 200 mM.