ABSTRACT Due to the limited ability of cartilage to repair itself, full-thickness articular defects of the knee have a poor prognosis. The healing response to full-thickness articular cartilage injury produces fibrous cartilage (type I collagen) rather than normal hyaline cartilage. The inferiority of fibrous cartilage may lead to secondary osteoarthritis. In young patients, the use of prosthetic replacement components is generally avoided owing to early failure difficulties. Biologic treatments include subchondral drilling, microfracture, autologous chondrocyte transplantation, mosaicplasty, and various cell-, tissue-, or growth factor-mediated processes. Fresh osteochondral bulk allografts (FOBAs) provide a potential biologic solution to focal and diffuse articular cartilage disease of the knee. FOBAs provide instantly viable, fully formed, normally contoured articular surfaces and can restore lost subchondral bone stock. Although the availability of donor tissue may be a challenge with this technique, once donor tissue is obtained, large amounts of graft are available for the management of lesions of almost any size. Further, FOBAs have demonstrated chondrocyte viability for up to 17 years after transplantation.While chondrocytes do not remain viable in frozen allografts, there is evidence that they do remain viable in fresh allografts with maintained matrix. This technique is now an established management option for the treatment of large osteochondral defects of the knee. Survivorships of 95% at 5 years and 80% at 10 years have been reported on the tibial side, and that of 85% was found at 10 years on the femoral side. The risk of transmitting infectious organisms, causing viral or bacterial disease, is one of the most concerning and controversial issues in the use of fresh allograft material. Graft viability is also an issue since many centers require a delay in implantation while waiting for culture results. At the authors' institution, grafts are typically used within 48-72 hours from procurement to maximize chondrocyte viability.