A TIA (Transient Ischemic Attack) is a sudden onset transient cerebral or retinal ischemic symptom. The definition of TIA has evolved from a time-based (< 24 hours) towards tissue-based. This requires brain scanning either with a computer tomography or magnetic resonance imaging. The benefit of urgent etiological work-up and immediate start of secondary preventive medications has been shown in two independent open studies, in which eight out of ten ischemic strokes could be prevented after a TIA. The risk of ischemic stroke is highest in the two days following a TIA. This puts a huge demand on both the patients and their doctors in the recognition of a TIA. The patient needs to be referred on an emergency basis to a specialized centre with adequate investigational facilities.