1. It has been shown that sodium bisulfate in an amount of 3–5% significantly shortens the reaction time compared with the most widely used catalysts in esterification of trimethylolpropane with fatty acids; it simplifies subsequent treatment of the reaction mixture, and increases the yield of ester. Changing the process temperature with the range 110–160°C does not affect the reaction time; therefore esterification with a yield of ester above 90% can be conducted at 110–120° C. 2. It has been shown that in the presence of sulfuric acid, on raising the experimental temperature from 110 to 160°C, the duration of the process is cut from 60 hrs to 1 h, but the yield of ester decreases significantly.