Abstract: Tannin acyl hydrolase (E.C.3.1.1.20) is commonly referred as tannase, hydrolyses ester and depside bonds of hydrolysable tannins to produce gallic acid, glucose and galloyl esters. Tannase finds application in many industrial sectors which includes pharmaceutical, food, chemical and beverages industry. The enzyme has potential uses in the treatment of tannery effluents and pre-treatment of tannin containing animal feed. Since, the discovery of tannase in 1867, a great deal of research did happen on production aspects of tannase. Most of the research was focused on fungal tannase, as tannin was earlier considered as bacteriostatic. After the discovery of bacterial tannase in 1983, several studies on bacterial tannase were published. Despite the long history and numerous publications, tannase is still considered as one of the costly industrial enzymes. This is due to less titer and long fermentation time of the processes. In view of the growing demand, it is imperative to isolate high productive strains and develop economically feasible processes. This study reviews the microbial sources, isolation and screening methods, modes of production, substrates and media, temperature and pH of fermentation, duration of fermentation and location of tannase enzyme. An attempt is also made to give an outline of historical development which has taken place in tannase research.