Objective To investigate the clinical features, treatment, and prognosis of 16 adult patients with a confirmed diagnosis of anti-N-methyl-D-aspartic acid (anti-NMDA) receptor encephalitis, which is easily misdiagnosed as viral encephalitis, in order to raise the awareness of this disease.Methods A retrospective analysis was performed for the clinical manifestations, laboratory examination, imaging data, treatment, and prognosis of 16 patients with anti-NMDA receptor encephalitis who were diagnosed and treated in Department of Neurology in Xiangya Hospital from December 2014 to June 2016.Results All patients had marked disturbance of consciousness, mental and behavior disorders, and seizure, and some patients experienced abnormal autonomic nervous function. Head MRI showed normal results or multiple lesions. Of all patients, 11 had anti-NMDA receptor antibodies in cerebrospinal fluid (CSF) and serum and 5 had anti-NMDA receptor antibodies only in CSF. After immunotherapy, 10 patients achieved a good outcome, and 6 had a poor outcome.Conclusions Early-stage anti-NMDA receptor encephalitis is easily misdiagnosed as viral encephalitis, epilepsy, or primary mental diseases. Anti-NMDA receptor antibody test should be performed for suspected patients as early as possible, and timely treatment can improve their prognosis.