Diffuse idiopathic skeletal hyperostosis is often incorporated into osteoarthritis. Although DISH often coexists with OA, patients affected by this disorder differ from patients with primary OA in several aspects: prevalence in the general population, gender distribution, anatomic site of primary involvement, magnitude and distribution in the spine and the peripheral joints. DISH is a distinct clinical entity. Its recognition as such should stimulate clinicians and researchers to focus on its pathogenesis, treatment and prevention.