The phenomenon of microbial biotransformation has gained significance regarding imitation of mammalian metabolism of drugs as well as rendering chemical diversity in these compounds via functionalization of unreactive centres enabling further modification of biologically active molecules. This can be attributed mainly to the diverse enzymatic machinery naturally present in microorganisms that transcends limited probability of structural diversity generated via conventional synthetic routes. It is more efficient/cost effective than using microsomal preparations from hepatocytes and raises no ethical issues such as those encountered with the dosing of animals. Another pertinent aspect of microbial biotransformation is bioremediation of hazardous chemicals in environment. Since fluorine atom is present in majority of pharmacological agents contamination of the environment by such compounds is worthy of separate study. This book describes microbial biotransformation of ezetimibe by two different fungi. Fungal enzymes acted on -OH group of propyl carbon as well as lactam ring. This book is useful for research students working in area of drug metabolism/development.