Aims: To determine the cost effectiveness and cost utility of arthrocentesis as an initial treatment for temporomandibular joint (TMJ) arthralgia compared to usual care. Methods: A two-armed, parallel-design, randomized controlled trial (RCT) was conducted in the Netherlands from January 2009 to June 2012 that included patients with TMJ arthralgia. Patients were randomly allocated to arthrocentesis (n = 40) or usual care (n = 40) for initial treatment. Arthrocentesis consisted of rinsing the intra-articular space with isotonic saline, and usual care included a soft diet, physical therapy, and splint therapy. The duration of the usual care program was 6 weeks, and follow-up was conducted 3, 12, and 26 weeks after its completion. Generalized estimated equation multivariate models were assessed in order to correct for the dependency of repeated measurements in the longitudinal data analysis. An independent samples t test was used to compare the arthrocentesis group with the usual care group for TMJ pain after 26 weeks. Cost effectiveness (total cost from a societal view) was related to TMJ pain (as measured on a visual analog scale [0 to 100 mm]) and to cost utility (quality-adjusted life years). Results: TMJ pain declined more quickly in the arthrocentesis group (n = 36) than in the usual care group (n = 36) (regression coefficient β = -10.76; 95% confidence interval [CI] = -17.75 to -3.77; P = .003). The estimated mean total (ie, societal) cost over 26 weeks was €589 (US $795) in the arthrocentesis group and €1,680 (US $2,266) in the usual care group. Arthrocentesis was associated with a lower mean cost and better health outcomes than usual care in 98% and 95% of the bootstrap simulations, respectively. Conclusion: The results of this study suggest that, from an economical perspective, arthrocentesis may be superior to usual care for the initial treatment of TMJ pain, as it had better health outcomes and lower costs than usual care. Schlagwörter: arthralgia, arthrocentesis, cost effectiveness, initial therapy, RCT, TMD