Intracranial vascular stenosis of haemodynamic significance is underappreciated both clinically and diagnostically. It is thought to be the cause of cerebral ischaemia in 8% of patients. Now it is possible to perform dilatation of the intracranial arterial stenosis by modern intraarterial angioplasty. Two cases are presented of successful dilatation of middle cerebral artery trunk stenosis. Diagnostic problems, follow up and pharmacological treatment as well as technique of intravascular treatment is described.