The extraction of lactoperoxidase (EC 1.11.1.7) from whey was studied using single step reverse micelles-assisted extraction and compared with reverse micellar extraction. The reverse micelles-assisted extraction resulted in extraction of contaminating proteins and recovery of lactoperoxidase in the aqueous phase leading to its purification. Reverse micellar extraction at the optimized condition after forward and backward steps resulted in activity recovery of lactoperoxidase and purification factor of the order of 86.60% and 3.25-fold, respectively. Whereas reverse micelles-assisted extraction resulted in higher activity recovery of lactoperoxidase (127.35%) and purification factor (3.39-fold). The sodium dodecyl sulfate polyaculamide gel electrophoresis (SDS-PAGE) profiles also evidenced that higher purification was obtained in reverse micelles-assisted extraction as compared of reverse micellar extracted lactoperoxidase. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 26: 763-771, 2010