Conclusion. The aetiology of Zenker's diverticulum is likely to be multifactorial. The geographical and racial variation in the prevalence and the rare familial cases suggest that genetic predisposition might have a role in the pathogenesis. The mode of inheritance in the rare possible familial cases seems to be autosomal dominant; recessive inheritance is non-existent or extremely rare. Objectives. To study the inheritance of Zenker's diverticulum. Subjects and methods. A detailed questionnaire concerning physical health and family history was sent to 122 patients with Zenker's diverticulum. Results. The prevalence of familial disease in Finland was found to be <2%. We found no evidence for genetic founder effect.