A 33-year old male patient, with Marfan's syndrome, reported symptoms of orthostatic intolerance and fatigue as a longstanding problem. Orthostatic cardiovascular examination showed poor orthostatic tolerance, with a rise in heart rate and a fall in arterial blood pressure and cerebral blood flow velocity. Self-discovered physical counterpressure manoeuvers improved symptoms, related to a substantial increase in arterial pressure and cerebral perfusion. When orthostatic complaints are reported by patients with Marfan's syndrome, physical counterpressure manoeuvers should be advised to reduce symptoms of postural hypotension.