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