Approximately two-third people of the world are accounted to having the problem of lactose intolerance and it reduces significantly their quality of life. This problem can be solved either by using supplementary probiotics microorganisms or using lactase enzyme in dairy products that hydrolyze the lactose present in food. But the use of microorganisms such as lactic acid bacteria as a probiotics is limited to treat the lactose intolerance due to its inability to form spore and endure the acidic environment of the stomach. Furthermore, the economic interest of lactse enzyme is related to its use in food industries, because of the deficiency of lactase in many people and thus, this enzyme has considerable industrial potential because they can give better yields at high temperatures. Moreover, microbial beta-galactosidases have a prominent position in terms of their role in production of various industrially relevant products like biosensor, lactose hydrolyzed milk, ethanol. This book, therefore, provides a simple technique for the isolation and characterization of lactase enzyme isolated from Lactobacillus bacteria extracted from Asian subcontinental equivalent card: Yogurt.