Abstract: The present invention relates to a process for preparing a triglyceride, comprising reacting glycerol with a polyunsaturated fatty acid having at least 20 carbon atoms and at least three double bonds or a C.sub.1-4 alkyl ester thereof, for a reaction time in the range of 24-48 hours at a temperature between 40.degree. and 80.degree. C. in the presence of a mixture of lipase A and lipase B obtained from Candida antarctica which is immobilized, to form (i) the triglyceride and (ii) water or a C.sub.1-4 alcohol, while removing the water or the C.sub.1-4 alcohol during the reaction, and recovering the triglyceride.