Eosinophilic granulomatosis with polyangiitis (EGPA) is a small vessel necrotizing vasculitis characterized by asthma and eosinophilia. Ischemic stroke is a rare complication of the disease. We herein report a case involving a 77-year-old woman with sinusitis who developed embolic stroke and splenic infarctions. Laboratory tests revealed hypereosinophilia and elevated troponin-T and N-terminal pro-brain natriuretic peptide. Antineutrophil cytoplasmic antibodies (ANCA) studies were negative. Skin biopsy showed infiltration of eosinophils into the arterial walls. These clinicopathological findings led to the diagnosis of EGPA. We also found the evidence of endomyocarditis as revealed by multimodality cardiac imaging. The patient underwent continuous immunosuppressive and anticoagulation therapy, and the infarctions did not recur. This report highlights the importance of histologically proven vasculitis with eosinophil infiltration and careful examination for cardiac involvement, especially in ANCA-negative patients.