AbstractMarine triglyceride oils (cod liver oil and oils from blubber of harp seal and minke whale) were reacted with glycerol using lipase as a catalyst at low temperature. A solvent‐free batch system with magnetic stirring was used. Solidification of the reaction mixture occurred, and a mixture of mono‐, di‐, and triglycerides was obtained in all cases. The recovered glyceride mixtures were solid at room temperature. The yield of monoglyceride (MG) and the fatty acid profile of the MG fractions were dependent on oil and the type of lipase used as a catalyst. Of the commercially‐available lipases investigated, lipase AK fromPseudomonas sp. synthesized the highest yield of MG (42–53%) at 5°C. These MG fractions were low in saturated fatty acids (4–11%) and high in long‐chain monounsaturated fatty acids (52–69%). The concentration of n‐3 polyunsaturated fatty acids was 12–20%.