Application of new biological treatments in orthopaedics is controversial nowadays. Surgeons and practitioners know how difficult can be to choose a solution for chondral injuries. Joint damages are from little contusions, osteochondral fractures, avascular necrosis, osteochondritis and degenerative processes like osteoarthritis and rheumatisms. All mentioned have a common problem: the lack of regenerating hyaline cartilage by themselves. Recently, PRP have been used to treat early moderate chondropathies. Here we show the preliminary results of 30 patients affected by chondropathy of the knee after 6 months treated with a single intrarticular injection of PRP. Thirty patients, 18-65 years old, with a diagnosis of I to III Outerbridge chondropathy in the knee, pain for more than 3 months following conservative treatment and no bone axial defect, were treated with one intraarticular injection of PRP (GPS mini set, BIOMET), after written consent and Ethic and Legal Committee approval. VAS and KOOS scores were evaluated before PRP injection and at 1, 3 and 6 months after the treatment. ANOVA with repeated measures using the SPSS showed significantly better results in term of KOOS and VAS scores at 1, 3 and 6 months respect to the pre-injection value (p less than 0,05) We think that PRP treatment is a promising alternative for the treatment of knee chondropathy; however its efficacy has to be demonstrated with more clinical works, with longer follow up and with greater number of patients, even with controlled and randomized trials. In our study only one injection of PRP has been able to allow a clinical improvement, suggesting the possibility to avoid multiple injections protocols, and consequently reducing the health expenses. Until the efficacy of PRP will not be definitely demonstrated, surgeon should be very prudent in indications.