BACKGROUND/PURPOSE: Congenital fourth branchial arch anomalies are uncommon entities, heretofore described only in case reports, affecting primarily children, and typically presenting as a cervical inflammatory process. The aim of the study was to collect appropriate data on the diagnosis, treatment, and outcome of this condition and to suggest guidelines for its management. METHODS: We conducted a structured review of the literature for cases explicitly identified as congenital fourth branchial arch anomalies or meeting anatomical criteria for this condition. We computed descriptive statistics and performed several post hoc 2-way comparisons of subgroups of cases. RESULTS: We located and critically evaluated 526 cases. Fourth arch anomalies were usually located on the left (94%) and generally presented as acute suppurative thyroiditis (45%) or recurrent neck abscess (42%). Barium swallow and direct laryngoscopy were the most useful diagnostic tools. Treatment options differed mainly in recurrence rates: incision and drainage, 89%; open neck surgery and tract excision, 15%; endoscopic cauterization of the sinus tract opening, 15%; and open neck surgery with partial thyroidectomy, 8%. Complications after surgery occurred primarily in children 8 years or younger. CONCLUSION: Fourth arch anomalies are more common than once thought. Treatment of these disorders with repeated incision and drainage yields high rates of recurrence; thus, complete excision of the entire fistula tract during a quiescent period appears preferable. Combining this surgery with partial thyroidectomy may further decrease recurrence rates. Complications can likely be minimized by using antibiotic treatment of acute infections or endoscopic cauterization in children 8 years or younger, and delaying open neck surgery.