Injury to tissue can cause significant disfigurement and loss of function. It may result from trauma, infections, birth defects and cancer surgery. When defects are too large for the patient's own body to repair the defect, reconstruction is required. Reconstruction of these defects can be performed using tissue from the patient's own body or with the aid of biomaterials and tissue engineering techniques. Several biomaterials are available to the plastic surgeon and they can serve as scaffold support for infiltrating cells in the ‘new tissue’ formation process. In this chapter, we discuss the basic principles of biomaterials, their interaction with cells and their role in tissue engineering. The advantages and disadvantages of autologous tissue transplantation, allografts, natural and synthetic biomaterials and their clinical applications are also described.