Idiopathic avascular necrosis of the carpal scaphoid, so called Preiser's disease, was first reported in the German literature in 1910 by Preiser. It is an exceedingly rare condition, the etiology of which is still unlnown, and the treatment is controversial. Recently, we treated a 68-year-old housewife who had avascular necrosis in the carpal scaphoid of her right hand and avascular necrosis of the lunate in her left hand. The plane X-ray, tomograms, bone scintigraphy and MRI, were useful in making the diagnosis of avascular necrosis of the catpal bones. The more symptomatic right hand was operated on by scapho-luno-capitate fusion, with a satisfactory postoperative course.