To describe chorea/ballism triggered by a hyperglycemic event. We used the electronic records system at Mayo Clinic–Rochester to identify patients diagnosed with chorea or ballism from January 1st, 2000 through December 31st, 2014. Each record was reviewed to confirm chorea/ballism. From these cases we selected those that developed chorea/ballism within a month after a hyperglycemic episode (blood glucose >300 mg/dL). Clinical, laboratory, and imaging findings were analyzed. Of the 596 chorea cases, we identified 7 patients (5 women) whose chorea was preceded by a hyperglycemic episode (range 3–30 days) during 15 years of surveillance, including new-onset diabetes in four cases. Median age was 80 years (range, 53–86). The chorea/ballism was unilateral in 6/7 cases and half of these unilateral cases had contralateral putamen T1-hyperintensity on brain MRI. After glucose correction, the chorea resolved within one week without recurrence in only one case. Among the 6 cases with persistent chorea, it was controlled with dopamine blocking/depleting medications. Chorea triggered by hyperglycemia is a rare complication of diabetes, with only seven cases identified at our tertiary medical center during 15 years of surveillance. This comprised about 1% of all chorea cases at our center during this time. Hyperglycemic chorea primarily developed in later life, with new-onset diabetes in the majority (4/7). Although MRI putamen T1-hyperintensity is reportedly typical, it was only seen in 3/6 cases. This MRI appearance may be mistaken for a hemorrhagic stroke, given the usual unilateral presentation. The chorea was controlled with dopamine blocking/depleting medications. •Hyperglycemia causes about 1% of acquired chorea, which is usually persistent.•Chorea developing within 1 month of an episode of hyperglycemia is suggestive.•Putamen T1 hyperintensity occurs in half and is often misdiagnosed as hemorrhage.•Advanced age and newly diagnosed type 2 diabetes are commonly seen.•Most cases are unilateral and responsive to dopamine blocking or depleting agents.