Transitory global amnesia (TGA) is an upheaval where the patient has anterograde memory lost of abrupt beginning and an inferior duration to 24 h, that has been related to ischaemic, epileptogenic and migranous ethiology. On the other hand polycythaemia is classified like a prothrombotic disorder that can produce manifold manifestations in the central nervous system, from strokes to psychiatric disturbances of anxious type, and all related to the secondary cerebral hipoperfusión due to hyperviscosity. Two patients, who had a previous diagnostic of polycythaemia suffered an episode of TGA, in addition in one of the two cases a cerebellar hemangioblastoma was found. There are numerous cases reported of brain tumors and other CNS findings diagnosed as a result of an episode of TGA, nevertheless on has not described to the relation between polycythaemia and the TGA. In the TGA a hypoperfusion of the temporal brain hemisphere has been documented and this can be a leading mechanism, so we propose that polycythaemia could ready to suffer a TGA.