Purpose: To evaluate the outcomes of living related conjunctival limbal allograft transplantation for the treatment of stem cell deficiency. Design: Retrospective, noncomparative case series. Participants: Nine living related donors, eight recipients (10 eyes) with Stevens-Johnson syndrome (3 eyes), ectodermal dysplasia (3 eyes), chemical injury (2 eyes), ocular cicatricial pemphigoid (1 eye), and atopic keratoconjunctivitis (n = 1). Intervention: Four clock hours of limbal conjunctival tissue from the best matched human leukocyte antigen (HLA) relative donor were transplanted to the recipient eye superiorly and inferiorly after conjunctival peritomy and removal of conjunctival pannus. Systemic cyclosporine was administered to all recipients. Main Outcome Measures: Restoration of corneal epithelium, reduction of vascularity and conjunctivalization, improved comfort, improved corneal clarity, and visual improvement. Results: Mean follow-up period was 26.2 months. Two highly inflamed eyes failed to initially epithelialize. The remainder all survived with restoration of corneal epithelium and reduction of vascularization. Corneal opacification was reduced (four of eight eyes) and visual improvement was achieved in seven eyes. All five eyes with pain had an improvement in symptoms. Allograft rejection occurred in two eyes (25%), and both were treated successfully. Both eyes had two class I HLA mismatches, and both had an underlying diagnosis of Stevens-Johnson syndrome. One eye developed a recurrent epithelial defect and perforated, requiring a penetrating keratoplasty that remained clear with an intact epithelial surface. The two initial failures also perforated and required penetrating keratoplasties that failed. None of the donor eyes had any complications. Conclusions: Restoration of the ocular surface by HLA-matched conjunctival limbal allograft transplantation can be accomplished in selected recipients. Systemic cyclosporine, even at low doses, is useful in ensuring long-term survival. Ophthalmology 2001;108:126-134 (C) 2001 by the American Academy of Ophthalmology.