The methyl and ethyl esters of milkweed (Asclepias) seed oil were prepared and compared to soybean esters in laboratory tests to determine biodiesel fuel performance properties. The pour points of the methyl and ethyl milkweed esters measured -6 degrees C and -10 degrees C, respectively, which is consistent with the high levels of unsaturation characteristic of milkweed seed oil. The oxidative stabilities measured by OSI at 100 degrees C were between 0.8 and 4.1 h for all samples tested. The kinematic viscosities determined at 40 degrees C by ASTM D 445 averaged 4.9 mm(2)/s for milkweed methyl esters and 4.2 mm(2)/s for soybean methyl esters. Lubricity values deter-mined by ASTM D 6079 at 60 degrees C were comparable to the corresponding soybean esters with average ball wear scar values of 118 pin for milkweed methyl esters and 200 mu m for milkweed ethyl esters. (C) 2006 Elsevier Ltd. All rights reserved.