We report multimodal evoked response studies in eleven children with ataxia telangiectasia. The ABRs were normal in all but one patient despite the severity of the disorder. The SERs were abnormal in all of the patients, the waveforms being either absent or of delayed latency, the abnormalities were more marked in the older patients. Abnormal motor and sensory nerve conduction studies were also found in all but the younger few patients. Most notably, the VERs were abnormal in all but 2, the older patients had delayed VERs and most had small amplitude responses. The electrophysiological profile of ataxia telangiectasia patients on the multimodal evoked responses differs from that found in certain other degenerative ataxias studied and may have some diagnostic utility.