OBJECTIVE There have been various incision and drainage methods for deep neck infection (DNI). Closed-suction drainage (CSD) has been used to decrease hematoma or to drain pus in other forms of medical surgery. The purpose of this investigation was to evaluate the usefulness of CSD for DNI. METHODS This study consisted of 30 patients who underwent CSD after incision and drainage for DNI between January 2006 and December 2011. The patients' demographics, systemic diseases, methods of airway control, involved spaces, incision, CSD results, duration of hospitalization, and complications were investigated. RESULTS CSD was used to treat 30 DNI patients. Eleven patients (37%) had underlying systemic diseases like diabetes mellitus, hypertension, hepatitis, asthma, etc. Twenty four patients (80%) had odontogenic infections in the mandibular molar region. Tracheostomy was performed in 5 patients (17%). The involved spaces were various from parapharyngeal space to mediastinum (mean: 4.8 spaces), and CSD was applied with drainage lines (mean: 3; 2-7 drains) over the course of 4-37 days (mean 14.6 days). The total amount of drained pus was 8-1344 cc (mean: 406 cc) and the daily amount was 1-61 cc (mean: 28 cc) from each patient. The mean length of hospital stay was 26 days, with a range of 9-83 days. Wound rupture happened in 7% of 56 total incision sites and spontaneous removal of the drain tube occurred in 3% of 91 total tubes. Four patients died because of cardiac arrest, pulmonary edema, and hypoxia. A statistical significance was accepted about total and daily amount of drainage at Pearson's correlation test (p < 0.001). CONCLUSIONS Accurate diagnosis, safe airway management, and early surgical drainage were important in DNI treatment. Compared to other drainage systems, CSD is clinically useful for treating DNI due to minimal incision, convenience of post-operative management, and less postoperative complications.