Tissue engineering approaches have enabled the development of methodologies that allow long-term, in vivo studies in epidermal biology. This has been accomplished through in vivo transplantation of human epidermal cells fabricated as three-dimensional, skin-equivalents in vitro. The methodologies presented in this chapter describe how skin-equivalent (organotypic) cultures are transplanted to nude mice to generate human skin grafts that normalize their tissue architecture, basement membrane structure and barrier function shortly after grafting. By grafting skin equivalents as composite cultures featuring well-differentiated human epidermis and fibroblasts in collagen gel, transplants are "primed" for accelerated take of grafted tissues. The methods outlined can generate stable, human epidermis that mimics the in vivo tissue.