Objective: To report a case of acquired demyelinating neuropathy that failed to improve upon treatment with intravenous immunoglobulins and plasmapheresis but responded dramatically to corticosteroids, illustrating the occasional difficulty in distinguishing Guillain-Barré syndrome (GBS) from a first attack of chronic inflammatory demyelinating polyneuropathy (CIDP). Clinical Presentation and Intervention: A 25-year-old previously healthy man was admitted with a 5-day history of ascending areflexic paralysis of all 4 limbs and diagnosed with GBS. On admission, he was administered intravenous immunoglobulins at a dosage of 400 mg/kg/day for 5 days yet continued to worsen. He became quadriparetic by the second week. As there had been no improvement, he was plasmapheresed with 7 sessions of plasma exchange, 50 ml/kg of plasma at each session, including appropriate replacement fluid. After failing to improve within 8 weeks, he was started on intravenous methylprednisolone and a dramatic improvement was observed by the 5th day. He continued to get better on oral prednisolone, was ambulatory with support 4 weeks later and could walk without support on follow-up. Conclusion: This case illustrates that there is a subset of patients initially diagnosed with GBS who do not respond to immunoglobulins or plasmapheresis but do specifically well on steroids. Hence treatment with prednisolone should not be delayed in selective cases of GBS as it may actually be a first episode of CIDP.