Twenty unselected patients with hypothyroidism were evaluated by clinical and electrophysiological techniques for neuromuscular dysfunction. On clinical examination, muscle weakness was observed in four, paraesthesia in 11, carpal tunnel syndrome in three, and peripheral neuropathy in two of the patients. The electromyograms were abnormal in 14 of the patients. The average duration of motor unit potentials and the mean amplitudes in these patients were reduced, compatible with myopathy. There were no denervation potentials. The nerve conduction abnormalities were found in 13 patients, predominantly affecting the median (10) than the peroneal nerve (one). Subclinical carpal tunnel syndrome was observed in six patients. This was evidenced by increased sensory in five and motor distal latencies in one patient.