Amylolytic enzymes are one of the oldest industrial enzymes and hold the maximum market share of enzyme sales. With the advent of new frontiers in biotechnology the spectrum of the application of the enzymes have expanded to major area of industry. Among different amylolytic enzymes, α amylase, β amylase and glucoamylase are the most useful and best known enzymes. This review focuses on the sources, structure-function and some important properties of the three amylolytic enzymes. Research is focused on improving enzymes, modifying them to achieve desired properties of the three enzymes.α-amylase uses double displacement mechanism whereas β-amylase and glucoamylase use single displacement mechanism.The active site of α-amylase contains a trio of acidic group s, β-amylase contains thiol groups, glucoamylase contains tryptophan.