This retrospective study examined whether arthrocentesis combined with 10 sessions of low-level laser therapy (LLLT) improved the clinical outcomes of patients with temporomandibular joint osteoarthritis (TMJ-OA) compared with arthrocentesis alone. Data from two groups of patients (total: n=36) with unilateral TMJ-OA were evaluated. The groups were established according to their treatment regimens: Group 1 (arthrocentesis alone; n=19) and Group 2 (arthrocentesis plus LLLT; n=17). All patients had been diagnosed in accordance with the Research Diagnostic Criteria for Temporomandibular Joint Disorders (RDC/TMD) (Axis I Group IIIb) protocol. They all underwent the same arthrocentesis protocol, but those in Group 2 also received 10 sessions of LLLT immediately afterwards.