Although COPD is a major disease worldwide there is a perplexing current uncertainty about the nature of this disease. COPD is characterized at onset and prevalently by the involvement of the lungs and bronchi, but as the disease evolves abnormalities develop in other organs and systems and the question arises: what is the pathogenesis of these respiratory and systemic impairments? Are the alterations that occur outside the respiratory system in the course of COPD a direct consequence of the lung pathology or is the lung simply the local expression of a pathological event whose origin lies in the organism as a whole? To tease out this issue, the Expert Opinion Consensus/Dissensus Seminar "COPD is/is not a systemic disease?" took place in Venice, on 13-14 November 2008. The Seminar was conceived and organized by the Italian Interdisciplinary Association for Research in Lung Disease, AIMAR. Top international opinion leaders in the respiratory field were invited to participate, the aim being to bring together sustainers of the two sides in a format allowing the best opportunity for an in-depth debate. Over the two days, different aspects of the issue 'upstream' (pathophysiology and biology) and 'downstream' (treatment and outcome assessment) were discussed. The general consensus that emerged, based on the still limited evidence available, was that COPD begins as a local inflammation in the lungs and this leads - through differentiated pathways yet to be fully clarified - to systemic consequences.