Idiopathic infantile arterial calcification (IIAC) was diagnosed radiologically in an infant with sudden onset of heart failure. The clinical picture, radiological, laboratory and postmortem findings, are described in detail. There was no family history and a metabolic abnormality could not be detected. Calcifications of major arteries and particularly ligaments are pathognomonic radiologic signs of this condition but diagnosis of IIAC during life has been established only rarely. The value of early diagnosis is emphasised.