In order to find the value of the antidromic sensory conduction between the wrist and the fourth digit in patients with symptoms and signs implying CTS, the following electrophysiological investigations were made and compared with each other on 59 patients and 21 normal healthy volunteers: the orthodromic sensory conduction velocity of the median nerve between the third digit and the palm, the palm and the wrist, the third digit and the wrist, and the wrist and the elbow; the maximal motor conduction velocity between the elbow and the wrist and the latency of the M response of the same nerve; the orthodromic sensory conduction velocity between the fifth digit and the wrist and the latency of the M response of the ulnar nerve; and the latencies of the sensory action potentials antidromicaly recorded from the fourth digit by stimulating the median and ulnar nerves at the wrist from equidistant points. In the study, the abnormality ratios in the patient group were found to be as follows: 1. Digit three-palm (sensory conduction velocity): 12.6 per cent; 2. Distal motor Latency (median nerve): 60.6 per cent; 3. Digit three-wrist (sensory conduction velocity): 54.5 per cent; 4. Digit three-digit five (sensory conduction velocity differences): 56.6 per cent; 5. Palm-wrist (sensory conduction velocity): 62.1 per cent; 6. Along digit four (antidromic sonsory conduction velocity differences of median and ulnar nerves): 84.7 per cent. In conclusion, it was found that the last-mentioned electrophysiological method is quicker and more sensitive than the others with 84.7 per cent abnomality.