Shuddering attacks are recognized as an uncommon benign disorder occurring during infancy or early childhood. It is necessary to distinguish these episodes from epileptic seizures. The attacks seem to involve shivering movements occurring daily for several seconds without impairment of consciousness. According to the criteria for benign myoclonus of early infancy, both shuddering attacks and benign myoclonus of early infancy should be regarded as having the same nosologic entity. I studied the pathophysiology of shuddering attacks in four children between 8 and 14 months of age using a video-electroencephalographic monitoring system. In one patient the frequency of shuddering movements, which was read as contamination of the electromyography on electroencephalography during attacks, seemed to be almost the same as that as of essential tremor. Shuddering attacks have decreased in number or disappeared in all four patients, but one exhibited mild abnormalities on magnetic resonance imaging and had relatives with epilepsy, and another had a flattened sella turcica. Although previous reports suggest that these movements are benign and needless investigations should be avoided, a problem related to the development of the nervous system may be present in children with shuddering attacks.