Data are lacking on correlations between changes in nerve conduction (NC) studies and treatment response in chronic inflammatory demyelinating polyneuropathy (CIDP). This report examined data from a randomized, double-blind trial of immune globulin intravenous, 10% caprylate/chromatography purified (IGIV-C [Gamunex]; n = 59) versus placebo (n = 58) every 3 weeks for up to 24 weeks in CIDP. Motor NC results and clinical measures were assessed at baseline and endpoint/week 24. Improvement from baseline in adjusted inflammatory neuropathy cause and treatment score correlated with improvement in proximally evoked compound muscle action potential (CMAP) amplitudes (r = -0.53; P < 0.001) of all nerves tested and with improvement in CMAP amplitude of the most severely affected motor nerve (r = -0.36; P < 0.001). Correlations were observed between improvement in averaged CMAP amplitudes and dominant-hand grip strength (r = 0.44; P < 0.001) and Medical Research Council sum score (r = 0.38; P < 0.001). Overall, the change in electrophysiologic measures of NC in CIDP correlated with clinical response to treatment.