Background: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) causes progressive disability due to weakness but responds to immunomodulating medication, including oral prednisone and intravenous (IV) immunoglobulin (IVIg). However, there is no consensus on initial therapy, and both of these treatments have drawbacks with long-term treatment. Objective: To review the efficacy and safety of high-dose, intermittent IV methylprednisolone (IVMP) as initial and long-term maintenance therapy for patients with CIDP. Design: A retrospective medical record review between 1992 and 2003 of outcomes in CIDP, comparing patients in 3 cohorts depending on whether their primary treatment was IVMP, IVIg, or oral immunosuppression with prednisone or cyclosporine. Setting: Washington University Neuromuscular Disease Center (St Louis, Mo), outpatient and inpatient records. Patients: Patients with clinical and electrophysiologic evidence of CIDP were identified. Of 57 patients, 39 had sufficient data for full analysis. Main Outcome Measures: Quantitative muscle testing with a handheld dynamometer. Medication profiles and adverse effects were also recorded. Results: There was no significant difference in the mean improvement in quantitative muscle testing at 6 months or at the last clinic visit (an average of 4.5 years later) among the 3 groups. Fewer patients treated with oral immunosuppression improved at 6 months, but at the last visit, 81% to 88% improved in all 3 groups. Less weight gain and fewer cushingoid features affected patients treated with IVMP (19%) compared with patients treated with oral prednisone (58%). Conclusions: Treatment of patients with CIDP using high-dose intermittent IVMP results in improved strength equal to that with IVIg and oral prednisone. The frequency of occurrences of weight gain and cushingoid features with IVMP is less than that with oral prednisone. Intravenous methylprednisolone should be considered for initial and long-term therapy in CIDP when patients have disability due to weakness.