Various options are available for the treatment of chondral and osteochondral lesions of the knee and the ankle. Among the therapeutic options currently available, cell therapy systems can be considered consolidated procedures. Autologous chondrocytes implantation (ACI) was first proposed by Brittberg in 1994 as a method to treat chondral defects. To overcome the inconveniences of the first technique, a second generation ACI technique was developed. With this technique, the harvested chondrocytes are cultivated, expanded, and then seeded directly onto a biocompatible and biodegradable synthetic membrane. The arthroscopic ACI technique has been developed with the aim to reduce the morbidity of the open technique, to compete more closely with the other arthroscopic options of treatment. It was first described by Marcacci and coworkers in 2002 for the treatment of chondral defects of the knee. Instead Giannini and colleagues first described their experience with arthroscopic ACI in the ankle in 2008. Here, we describe the technique of the implantation of autologous chondrocytes, seeded on collagen membranes, fixed by fibrin glue by an all arthroscopic technique for the treatment of chondral lesions of the knee and the ankle.