Regenerative medicine has shown good potential in regenerating tissues and organs. Tissue engineering, as a sub-branch of this technology, helps the process of tissue and organ regeneration by using enginenering techniques. Biomaterials play a pivotal role in the success of tissue engineering. Of course, challenges such as the origin of biomaterials, synthesis and extraction, biocompatibility and cell adhesion, scaffold design techniques, and physical, chemical, and mechanical properties of scaffolds designed with synthetic biomaterials can create limitations inlimit their use in scaffold design. A promising option for designing scaffolds is the use of tissues and extracellular matrix (ECM). By removing cellular factors and inflammatory factors, a unique microenvironment called the decellularized extracellular matrix (dECM) is prepared, which regulates and directs cellular processes. In this chapter, we discuss various decellularization techniques to preserve the structural, physicochemical, and biological properties of dECM products and some of its applications in tissue regeneration.