Lipid formation and γ‐linolenic acid (GLA) production by 48 species of Mucorales fungi grown on sunflower oil (which consists of 70% linoleic acid ; LA) were studied. The strains accumulated 42·7–65·8% lipid in biomass (7·66–13·39 g l−1). Eight cultures produced more than 200 mg GLA l−1. Highest GLA yields exhibited Mucor mucedo CCF‐1384 and Cunninghamella echinulata CCF‐103 (379 and 373 mg l−1, respectively). Mortierella alpina CCF‐185 synthesized 465 mg l−1 arachidonic acid. While the decrease of LA utilization index (ratio of LA content of cell lipid/LA content of oil source) was accompanied with growth of delipidized biomass and with reduction of lipid accumulation within the cells, high lipid yield was as a consequence of the direct oil source incorporation into intracellular lipid.