Biodiesel, an alternative diesel additive made from renewable sources, has problems associated with their cloud points when used in colder climate. One method of improving the cloud point of biodiesel is hydroisomerization which branches the saturated portion of the biodiesel and lowers the cloud point of the compound. Palmitic acid methyl ester, which is the major saturated fatty acid in vegetable oils, is hydroisomerized with a 5 g kg(-1) Pt impregnated beta zeolite catalyst at reaction conditions 200-285 degrees C and 1.0-4.0 MPa H-2 pressure. FTIR and GC/MS analyses confirmed the branching and the identity of the reaction products. The cloud point of the material was lowered from 30 degrees C to 20 degrees C under reaction conditions of 285 degrees C and 4.0 MPa H-2 pressure at the yield of 42% after 16 h. This study reports the hydroisomerization reaction being successful in branching the starting material in order to lower the cloud points of methyl esters. (C) 2012 Elsevier Ltd. All rights reserved.