The matrix-induced autologous chondrocyte implantation (MACI; Verigen, Leverküsen, Germany) is a tissue engineering technique for the treatment of deep chondral lesions. Cultured chondrocytes are seeded on a collagen membrane that can be implanted into the defect using exclusively fibrin glue. These features imply some surgical advantages with respect to the traditional ACI technique, such as the possibility of performing the procedure in articular sites, in which putting stitches for the periosteal patch is impossible. We report on the arthroscopic MACI technique for the treatment of a chondral defect of the knee. A 25-year-old man suffered persistent pain at the left knee after a violent direct trauma. Magnetic resonance imaging (MRI) and arthroscopic examination at the time of cartilage biopsy revealed a 2-cm2 chondral lesion in the posterior portion of the lateral tibial plateau. The implantation procedure was performed through traditional arthroscopic portals, and the seeded membrane was fixed with fibrin glue, excluding water flow temporarily. Implant stability was verified intraoperatively, and filling of the defect was shown 12 months after surgery by MRI, which showed a hyaline-like cartilage signal. In this specific case, the arthroscopic approach allowed to achieve an optimal view of the lesion, without sacrificing any tendinous or ligamentous structure of the knee.