Objective To investigate the clinical features of patients with anti-glutamic acid decarboxylase 65 （GAD65） encephalitis.Methods A retrospective analysis was performed for the clinical data of nine patients with anti-GAD65 encephalitis who attended Department of Neurology， Xiangya Hospital of Central South University， from April 2016 to March 2022.Results The nine patients had an age of onset of 14-76 （31.2±20.5） years and a male/female ratio of 4：5， and one patient had the history of preceding infection. The analysis of initial symptoms showed seizure in three patients， headache in two patients， dizziness in one patient， hearing loss and olfactory hallucination in one patient， involuntary movement in one patient， and facial paresthesia in one patient. As for clinical manifestations， there were five patients with limbic encephalitis， one patient with seizure alone， one patient with limbic encephalitis and cerebellar ataxia， one patient with stiff-person syndrome and brainstem encephalitis， and one patient with seizure， stiff-person syndrome， and cerebellar ataxia. Among the nine patients， two patients had insulin-dependent diabetes， one patient had hyperthyroidism， and four patients had positive thyroid peroxidase antibody. All nine patients underwent brain MRI， among whom three patients had abnormal signal in the hippocampus or the temporal lobe and one patient had cerebellar atrophy. Seven patients underwent electroencephalography during the acute stage， and four patients had epileptiform discharge involving the frontotemporal region， among whom three patients had the involvement of both sides. All nine patients received immunotherapy， among whom three received first-line therapy alone and 6 received both first- and second-line therapies. Six patients received antiepileptic treatment， among whom four required the combined use of two or more antiepileptic drugs. All nine patients were followed up， and one patient was lost to follow-up. Six patients had good prognosis， among whom two patients had complete remission of symptoms and 4 had partial remission with the sequelae of seizure， ataxia， and mental and behavioral disorders； two patients had no remission of symptoms.Conclusions Anti-GAD65 encephalitis is commonly seen in young and middle-aged people， with slightly more female patients than male patients. Main clinical manifestations include limbic encephalitis， stiff-person syndrome， and cerebellar ataxia， with the overlap of symptoms in some cases. The diagnosis of this disease depends on the detection of high-titer GAD65 antibody in serum. Epilepsy is often difficult to control， and most patients have good response to immunotherapy. Therefore， immunotherapy should be initiated as early as possible to improve prognosis. ［Journal of International Neurology and Neurosurgery, 2022, 49(6): 18-22］