Eminectomy with or without a subsequent discoplasty was performed on 30 patients (36 joints) with internal derangement of the temporomandibular joint (TMJ) confirmed either arthrographically or with magnetic resonance imaging. The importance of the inclination of the TMJ eminence and the therapeutic value of eminectomy are discussed. The TMJs were clinically evaluated before and at least 1 year after surgery in respect to opening function and symptoms. The results were promising (86.8% of the patients felt better). In five patients with a preoperative diagnosis of anterior disc displacement with reduction, only an eminectomy was performed. In these five cases eminectomy alone was sufficient to restore normal TMJ function.