Over a period of 7 years, among 175 boys under the age of 16 years with familial Mediterranean fever (FMF), 16 (9%) developed 28 episodes of scrotal swelling that was unilateral in 26 (93%) and bilateral in 2 (7%). Fever and pain were present in 15 (94%) children; fever was characterized by a gradual onset and pain was moderate in intensity. The episodes were self-limiting and lasted from 8 h to 5 days. Scrotal swelling was the presenting feature of FMF in 4 (25%) patients. Six (38%) children underwent surgery; the operative findings, available in 3, showed a normal testis and epididymis and inflammation of the tunics vaginalis. The self-limiting nature of the episodes lasting for a few days was similar to the clinical course of serositis seen in FMF. This strongly suggests that inflammation of the tunica vaginalis, resulting in scrotal swelling, is another feature of FMF serositis. The gradual onset of fever, pain, swelling, and recurrence in a boy of Mediterranean origin, especially in the presence of a relevant family history, strongly points toward the diagnosis of FMF and conservative management. Early diagnosis and prophylactic colchicine therapy are expected to avert recurrences, which may result in ischemic testicular necrosis and FMF nephropathy.