Two brothers with Thiemann's disease are described and the accumulated world literature is briefly reviewed. Thiemann's disease is considered to be a form of idiopathic avascular necrosis of the PIP joints of the hands, with occasional involvement of other joints. The characteristic deformity and x-ray findings are reviewed. Thiemann's disease is a genetic disorder and, in families in which detail is available, is inherited as an autosomal dominant with virtual complete penetrance.