The fresh osteochondral allograft is an established procedure for reconstructing joint surface defects, especially in the knee. The best results are obtained in young patients who have posttraumatic joint surface defects before the onset of secondary degenerative changes. Fresh tissue is preferred because of its potentially greater chondrocyte viability as compared to frozen, irradiated, or cryopreserved tissue. Donor selection is based on the same criteria as multiple organ donation. The ideal donor is younger than 30 years of age, and the donor joint must not be damaged. Transplantation should be performed within 24 h of graft procurement. Menisci may be included in the allograft. Malalignment should be corrected by osteotomy so that the resultant biome-chanical axis passes through the nonallografted compartment. Immunological factors are less important than biomechanics in determining the outcome. Success rates as high as 79% may be achieved in properly selected patients. This article reviews patient selection, graft procurement, surgical technique, postoperative care, immunological factors, and results in fresh osteochondral allografting.