The mechanisms involved in the genesis of chronic obstructive pulmonary disease (COPD) are poorly defined. This area is complicated and difficult to model because COPD consists of 4 separate anatomic lesions (emphysema, small airway remodeling, pulmonary hypertension, and chronic bronchitis) and a functional lesion, acute exacerbation; moreover, the disease in humans develops over decades. This review discusses the various animal models which have been used to attempt to recreate human COPD and the advantages and disadvantages of each. None of the models reproduces the exact changes seen in humans, but cigarette smoke-induced disease appears to come the closest and genetically modified animals also, in some instances, shed light on processes that appear to play a role.