The aim of the present study was to report the 1-year therapeutic outcome of intra-articular injections of high-molecular-weight hyaluronic acid (HA) without arthrocentesis in a group of 25 patients with osteoarthritis (OA) of the temporomandibular joint (TMJ). The results were compared with those of a group of 10 patients with OA of the TMJ, treated with nonsteroidal anti-inflammatory drugs.Twenty-five patients (group A) underwent a cycle of 5 injections of HA into the TMJ. Ten patients (group B) underwent a therapy with nonsteroidal anti-inflammatory drugs for 1 month. The follow-up assessments after the end of treatment were at 1, 3, 6, and 12 months.Regarding the first follow-up (1 month), statistical analysis for all clinical parameters showed no significant differences (ie, beneficial effect for 2 groups) between groups A and B (P > 0.001). Significant statistical differences (ie, encouraging effect for group A) for all clinical parameters were recorded 1 year after the end of treatment between groups A and B (P < 0.001).A cycle of 5 intra-articular injections of HA without arthrocentesis for patients with OA of the TMJ is considered successful at 1-year follow-up period.