A 67-year-old right-handed woman experienced a sudden anterograde and retrograde short-term memory deficit that recovered on the next day. Magnetic resonance imaging (MRI) showed a spotty high-intensity lesion in the left putamen in the diffusion-weighted and fluid-attenuated inversion recovery images. Transient global amnesia due to lacunar infarction of the left putamen was diagnosed. Transient global amnesia is characterized by a sudden onset of anterograde amnesia that disappears within 24 hours. The cause of transient global amnesia is still uncertain. Some studies with MRI showed small lesions in the hippocampus at 24-74 hours after the episode. These lesions disappear within several weeks. However, our case of transient global amnesia showed a small lesion in the left putamen, not the hippocampus. Some studies with functional MRI reported that the stratum plays an important role in short-term memory and cognitive function. This case showed only a left putamen lesion, which indicates that a putamen lesion can cause transient global amnesia.