A 69 years old male with erectile dysfunction lasting 2 years, took 50 mg of sildenafil for having sex with his wife at about 6 o'clock in the morning. One hour later his wife detected that he had an anterograde memory impairment: this was interpreted as a confusional state. The neurological examination suggested a transient global amnesia (TGA). EEG and cerebral magnetic resonance imaging were non-informative and memory deficits resolved within 24 h. Therefore, a TGA was diagnosed. Since no other trigger was detectable, sildenafil was deemed responsible for its occurrence.