Deep neck infection may be lethal, especially when life-threatening complications occur. We conducted a retrospective analysis of 184 patients with deep neck infection who were treated at Kaohsiung Medical University Hospital during the past 6 years. Factors such as age, sex, hospitalization days, clinical presentations, involved spaces, imaging studies, microbiology, and treatment method were analyzed. There were 122 men and 62 women with a mean age of 41.7 years. The average hospitalization was 8.4 days. The involved spaces, determined by physical examination and radiologic findings, were the peritonsillar space (59 patients), parapharyngeal space (77 patients), submandibular space (55 patients), and retropharyngeal space (20 patients). Of the 49 patients for whom the origin of infection was identified, 29 were infected via the upper respiratory tract and 13 had infection of odontogenic origin. The most common isolated organism was Klebsiella pneumoniae. One hundred and thirty-seven patients (74.5%) underwent surgery, including repeated needle aspiration (87 patients) and surgical drainage (50 patients). The remaining 47 patients recovered uneventfully with antibiotic therapy alone. Eighteen patients developed life-threatening complications, such as descending mediastinitis, sepsis, airway obstruction, and jugular vein thrombosis. Two patients died of septic shock. The combination of accurate diagnosis, effective antibiotic therapy, airway maintenance, and intensive surgical debridement for those who fail to respond to conservative treatment will lead to a good prognosis.