This study compared sensitivity, specificity, positive and negative likelihood ratios (LR) of four previously published sets of electrodiagnostic criteria for demyelination in 64 patients whose history and physical examination indicated that chronic inflammatory demyelinating polyneuropathy was a possible diagnosis. Sensitivity of the sets of criteria ranged from 56-70 % and specificity from 85-98 %. Positive LRs ranged from 4.67-28 and negative LR's from 0.35-0.45. The results showed that one set of electrodiagnostic criteria was considerably more helpful than the other three in establishing the diagnosis CIDP. If, however, the test results of the sets were not consistent with demyelination, the effect of the negative test results on the probability of the diagnosis CIDP was similar for all four sets.