A case demonstrating the serial development of "de novo" aneurysms following common carotid ligation is presented. Persistence of the hemodynamic changes caused by carotid ligation, proven by ophthalmodynamometry performed twenty-five years later, might be the underlying basis for the serial formation of de novo aneurysms. The need for a program of routine neuroradiological follow-up in patients undergoing carotid ligation is discussed.