PURPOSE: Neck masses, in pediatric population, derive from a multitude of congenital, inflammatory, or neoplastic diseases. The majority of these masses represent benign conditions. However, thorough clinical evaluation is required to rule out malignant diseases. We evaluated the causes, clinical characteristics and outcomes of children with neck masses who underwent tissue biopsy. METHODS: A total of 28 medical records of children with neck mass who underwent tissue biopsy at Chungnam National University Hospital, from January 2000 to March 2004 were retrospectively analyzed. The methods of biopsy were ultrasonography guided core biopsy (CB), fine needle aspiration biopsy (FNAB) and excisional biopsy. RESULTS: Out of 28 patients, half were boys. The most common location of the mass was the posterior cervical area (N=19, 67.9%). Laboratory findings of peripheral blood and serologic studies were nonspecific. In 25 (89.3%) cases, CB or FNAB was initially performed for neck masses. Among them 10 cases (40%) were reactive hyperplasia, 8 (32%) inflammatory granulation tissues, 4 (16%) necrotizing lymphadenitis, and 3 (12%) acute suppurative inflammations. Initially, excisional biopsy was performed for diagnosis in 3 (10.7%) cases. Diagnosis of these cases was thyroglossal duct cyst, dermoid cyst and lymphoblastic lymphoma, respectively. CONCLUSION: Most neck masses in children were benign. CB and FNAB were safe methods for tissue sampling, without need for general anesthesia.