Objectives This study investigated the clinical and radiological features of antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) patients with acute brain infarction, using a cohort of Korean patients with AAV. Methods This study included 263 patients with AAV. Acute brain infarction was defined as infarction that occurred within 7 days or less. The brain territories affected by acute brain infarction were investigated. Active AAV was arbitrarily defined as the highest tertile of Birmingham Vasculitis Activity Score (BVAS). Results The median age at diagnosis was 59.0 years, and 35.4% were male. Fourteen cases of acute brain infarction occurred in 12 patients (4.6%), which was calculated as 1332.2 per 100,000 patient-years and 10 times higher than the incidence rate in the Korean general population. Patients with AAV with acute brain infarction exhibited significantly older age, increased BVAS at diagnosis, and a more frequent history of prior brain infarction compared with those without. The brain territories affected in AAV patients were middle cerebral artery (50.0%), multiple territories (35.7%), and posterior cerebral artery (14.3%). Lacunar infarction and microhemorrhage were observed in 42.9% and 71.4% of cases, respectively. Prior brain infarction and BVAS at diagnosis were independently associated with acute brain infarction (hazard ratios, 7.037 and 1.089). Patients with AAV with prior brain infarction or BVAS for active AAV exhibited significantly lower cumulative acute brain infarction–free survival rates than those without. Conclusion Acute brain infarction was observed in 4.6% of AAV patients, and both prior brain infarction and BVAS at diagnosis were independently associated with acute brain infarction.