Background: Branchial cleft cysts are the most common neck masses in children. USG and MRI allow precise diagnosis and preoperative assessment of these changes. Case report: A 20-month-old girl was admitted to the hospital with a palpable mass in the submandibular region. In the USG and MRI examinations, a cystic mass was found. The cyst was removed. Histopathological examination revealed the presence of an endodermal cleft cyst. Conclusions: The main cause of neck tumors in children are congenital changes. The most common are branchial cleft cysts and thyreoglossal cysts. Branchial cleft cysts arise during the first six weeks of fetal life when the branchial arches are developing. Among them the most common are second branchial cleft cysts, which occur in the neck, anterior to the sternocleidomastoid.