Preparation and properties of four triesters-derivatives of 9,10-dihydroxystearic acid after the epoxidation of methyl ester of the oleic acid, opening of the formed oxirane ring in suitable medium and esterification of free hydroxyl group is discussed in the paper. Removal of the double bond from acyl of the fatty acid, increase of the molar weight and change of molecular structure resulted in increase of viscosity and oxidation stability of prepared triesters. Lubrication tests performed on a four-ball machine showed better tribological characteristics of synthesized triesters when compared with mineral additive-free base oil. (c) 2007 Elsevier Ltd. All rights reserved.