The reaction of transesterification of rapeseed oil in ethanol under supercritical fluid conditions in the 320-380 I mu C temperature range, under 30 MPa pressure, for ethyl alcohol to rapeseed oil molar ratios of (6-20):1 was studied experimentally. Dependencies of kinematic viscosity of the reaction product on the temperature, molar ratio of the starting reagents, and duration of reaction implementation were obtained. A correlative dependence that allows calculation of the content of ethyl esters of fatty acids in the transesterification product is proposed using experimental data on the kinematic viscosity values of the reaction product.