The efficacy, safety and cost-effectiveness of immunomodulatory drugs remain largely unclear given the limited number of studies that were identified. Two studies met the inclusion criteria for this review. One was a systematic review of randomized and quasi-randomized studies while the other was a European clinical practice guideline that covered the diagnosis and treatment of CIDP. Among the trials identified within the systematic review, no significant benefit from interferon beta-1a or methotrexate was observed in patients receiving these immunomodulators as an adjunctive agent to IVIg. Based on consensus reached by clinical experts, the clinical practice guideline recommended adding an immunosuppressant or immunomodulator only if response to therapy is inadequate or if one desires a lower dose of the maintenance therapy, and the remaining first-line treatments alternatives have been tried without success.