A process for preparing lipids which contain docosahexaenoic acid (DHA) and/ordocosapentaenoic acid (DPA) is disclosed. The process includes the steps ofcultivating in a medium a microorganism which belongs to the genus Ulkeniahaving the ability to produce DHA and/or DPA and recovering the lipids fromthe culture. The process may further include the step of separating DHA and/orDPA from the lipids.