The clinical picture of transient global amnesia (TGA) is discussed on the basis of the clinical findings in 19 patients. The central symptom is an acute memory loss, leading to disorientation, helplessness and pseudo-confusion. The symptoms last for several hours and then fade away. Pathogenetically a functional impairment of the limbic system is proposed. Most cases of TGA are due to ischaemic disease; rare causes are epileptic seizures, tumours, encephalitis and toxic or metabolic conditions. In order to clarify the aetiology and initiate appropriate therapy meticulous neurological investigation is necessary. The spontaneous prognosis of ischaemic forms is favourable, whilst in other cases it depends on the primary condition.