Decellularized tissues and organs have been successfully used in a variety of tissue engineering/regenerative medicine applications, and the decellularization methods used vary as widely as the tissues and organs of interest. The efficiency of cell removal from a tissue is dependent on the origin of the tissue and the specific physical, chemical, and enzymatic methods that are used. Each of these treatments affect the biochemical composition, tissue ultrastructure, and mechanical behavior of the remaining extracellular matrix (ECM) scaffold, which in turn, affect the host response to the material. Herein, the most commonly used decellularization methods are described, and consideration give to the effects of these methods upon the biologic scaffold material.