Objective To study the clinical manifestations and neuroimaging characteristics of patients with hemichorea-hemiballismus (HC-HB) induced by nonketotic hyperglycemia. Methods The clinical data, laboratory findings and neuroimaging findings of 5 patients with HC-HB induced by nonketotic hyperglycemia who were treated in Changhai hospital of Second Military Medical University were retrospectively analyzed. The 5 patients included 4 females and 1 male, ranging 65-83 years old and averaging (76.6±7.2) years old. Results All the five patients presented an acute onset, with four of them having chorea or ballismus involuntary movement in unilateral limbs and face and one having generalized chore. The highest levels of blood glucose in patients at onset were 18.6-44.6 mmol/L (averaging[26.6±10.5] mmol/L), with negative urine ketone. T₁-weighted imaging showed hyperintensity in contralateral basal ganglia in 4 cases and in bilateral basal ganglia in 1 case, with no edema or mass effect; most T₂-weighted imaging was of isointensity. Increased protein levels and normal number of cells were observed in 3 cases in cerebrospinal fluid examination, and two of three cases had increased IgG index or 24 h intrathecal synthesis rate, which was relieved by effective control of blood glucose combined with pharmacotherapy, such as haloperidol. Conclusion Nonketotic hyperglycemia and HC-HB are the characteristics of HC-HB induced by nonketotic hyperglycemia, with hyperintensity on T₁-weighted MRI imaging in the contralateral basal ganglia or in bilateral basal ganglia occasionally. Early diagnosis and proper treatment of those patients can achieve good prognoses.