Tissue expansion is of value in the repair of some defects produced by Mohs micrographic surgery. In particular, defects of the nose, forehead, temple and scalp as well as extensive defects in other areas may require expansion. Tissue expansion should be considered prior to Mohs micrographic surgery in these cases. Intraoperative and rapid expansion are useful adjuncts to other repair options. Complications of expansion are frequent and must be anticipated.