The aim of tissue engineering is to combine the disciplines of engineering and biology to help the body's own regenerative mechanisms to repair diseased or damaged tissue to its original state and function. One strategy is to seed a patient's progenitor cells on a scaffold, which will act as a support and stimulus of tissue growth. The cells will lay down tissue in the shape of the scaffold and this biocomposite can be implanted into a defect with the scaffold dissolving as the tissue regenerates. Scaffold design is one of the important aspects of this strategy and will be discussed in this entry. The entry discusses the criteria for an ideal scaffold and the use of bioinert, bioresorble, and bioactive materials. The use of polymers, ceramics, glasses, and composites as scaffold materials and the processing techniques used to create tissue scaffolds are described and the advantages of using each material and each processing technique are discussed.