Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis that commonly affects the peripheral nervous system. EGPA rarely presents with acute polyneuropathy resembling Guillain-Barré syndrome (GBS). A 51-year-old female patient with a history of asthma suddenly developed bilateral lower extremityparesthesia that progressed to asymmetric ascending paralysis within 10 days of onset. Nerve conduction study results were compatible with acute motor sensory axonal neuropathy, consistent with a GBS subtype. A clinical and neurophysiological diagnosis of GBS was made, and high-dose intravenous immunoglobulins were administered. However, the patient's painful motor weakness persisted. Furthermore, she had newly developed skin lesions on her back, face, and arms. Her blood test revealed marked eosinophilia (>60%). In addition, antineutrophil cytoplasmic antibodies were reported positive. A Water's view radiographic image showed bilateral maxillary sinusitis. Considering the history of asthma, we suspected EGPA-associated polyneuropathy and started steroid treatment. The patient's strength and eosinophilia improved rapidly and dramatically. EGPA can mimic GBS and should be differentiated because of different treatment strategies. Early diagnosis and prompt treatment help achieve a good outcome.