Several similarities have reported between patients suboptimal level of vitamin D and patients with Chronic Obstructive Pulmonary Disease (COPD): both conditions are more prevalent after the 6th decade and are associated with impaired defense mechanisms, with skeletal muscles dysfunction and with an early ageing process. We have reviewed the literature concerning the interrelationship between the main pathophysiological processes of both conditions, in order to emphasize the influence of vitamin D deficit on COPD development and evolution. Epidemiological, clinical and experimental data supporting this association are presented. We concluded that the identification of common pathophysiological mechanisms for the vitamin D deficiency and COPD substantiates the hypothesis of the involvement of this hormone in the chronic obstructive pulmonary disease.