Electrophysiological examinations were performed on 32 children aged three to 17 years who had typical clinical manifestations of ataxia-telangiectasia (AT). EMG findings demonstrated neurogenic lesions, more pronounced in the distal leg muscles of older children where they resembled the picture characteristic of motor neuron disease. Electrophysiological and nerve conduction results showed that generalised, progressive, sensory nervous system degeneration, with neurogenic amyotrophy affecting the distal part of the lower limbs, is an established feature of this disease and can be considered one of the diagnostic characteristics of AT. This allows the syndrome to be classified as an hereditary spinocerebellar degeneration.