Summary1. Applying the method Age‐Correction besides Amplitude Scaling, each of 87 SERs recorded from 87 CO‐poisoned subjects was converted into the Age‐Corrected SER Patterns.2. Averaging the Age‐Corrected SER Patterns, Age‐Corrected IPA‐SER Patterns were obtained respectively with the severe and mild cases.3. In the Age‐Corrected IPA‐SER Pattern, the latencies of P1, N3, P3and P4were larger with the severe cases than with the mild cases, resulting in the ratios of 120, 107, 127 and 113% respectively. The amplitude between P2and N3was larger with the severe cases than with the mild cases, resulting in the ratio of 112%.4. The rate of coincidence of the discrimination of the severe and mild cases by the Age‐Corrected SER Patterns with the clinical graduation of each subjects attained to 85.7 and 72.7% respectively with the severe and mild cases, and to 75.9% in all.5. Considering also the results of the previous studies, these results of the present study verified the validity of the meth