The incidence of clinically and roentgenologically manifest Kienböck disease was checked on the basis of a thorough analysis of 85 patients suffering from the condition. Apart from sex distribution and age at onset, particular importance was attached to certain "constitutional factors". The fact in all bilaterally affected patients the ulnar was smaller than average at the wrist, and the advanced signs of arthrosis were radiologically demonstrated in 81.8% of the patients, once again confirms that certain constitutional factors play a decisive role in the Pathogenesis of Kienböch disease. Their importance for treatment, and also for possible assessments for insurance purpose, is emphasized.