The treatment of solitary bone cysts remains controversial. The high recurrence rate after operative treatment calls for the search of new effective treatment methods. The aim of this study was to evaluate the outcomes of treatment of solitary bone cysts with platelet-rich plasma (PRP) and allogenic bone grafts. The study group consisted of 9 patients (4 males and 5 females) with the diagnosis of solitary bone cyst. Their mean age was 12 years and 2 months (range: 6 to 17 years). All patients were symptomatic in routine daily activities. There was a coexisting fracture within the cyst wall in three patients. The operative procedure included removal of the cyst wall soft-tissue lining and filling of the cavity with deep frozen, gamma irradiated morselized allogenic bone grafts mixed with PRP. The PRP was prepared preoperatively with the GPS System (Gravitational Platelet Separation System, Biomet Merck). In six patients with an existing or impending fracture in particularly large cysts, fixation was used. For the cysts located close to the epiphysis (2 femurs, 1 humerus) we used an IM nail or DHS. For three cysts located in the diaphyseal region of the humerus we used an Ilizarov fixator. Three cysts with lower risk of impending fracture were left without fixation. The mean follow-up period was 19.5 months (range: 12 to 30). We noted no procedure-related complications and no refracture during the observation period. Bleeding from the wound was minimal, possibly as a result of PPP use. The wounds healed without swelling or excessive scar formation. After 12 months all the cysts were completely filled with new bone and were staged as Neer stage I. All the patients were asymptomatic. The use of PRP with allogenic bone grafts appears as a promising method for the treatment of solitary bone cysts. Further studies on larger patients series with longer follow-up will be necessary to answer the question whether this method will provide a lower recurrence rate compared to other forms of treatment.