Lipases (triacylglycerol acylhydrolase, EC 126.96.36.199) are part of the family of hydrolases that act on carboxylic ester bonds. The physiologic role of lipases is to hydrolyze triglycerides into diglycerides, monoglycerides, fatty acids, and glycerol. These enzymes are widely found throughout the animal and plant kingdoms, as well as in molds and bacteria. Of all known enzymes, lipases have attracted the most scientific attention. In addition to their natural function of hydrolyzing carboxylic ester bonds, lipases can catalyze esterification, interesterification, and transesterification reactions in nonaqueous media. This versatility makes lipases the enzymes of choice for potential applications in the food, detergent, pharmaceutical, leather, textile, cosmetic, and paper industries. The most significant industrial applications of lipases have been mainly found in the food, detergent, and pharmaceutical sectors. Limitations of the industrial use of these enzymes have mainly been owing to their high production costs, which may be overcome by molecular technologies, enabling the production of these enzymes at high levels and in a virtually purified form.