The emerging role of quantitative computed tomography (CT) in the evaluation of pulmonary emphysema is reviewed. CT is primarily used in the clinical setting to assess lung morphology visually. Increasingly treatments are being developed to treat patients with emphysema that require accurate quantitation of extent and distribution of the process. In addition, functional assessment can be made by inference of detailed anatomic correlates and by direct measurement of regional function using dynamic scan protocols. The aim of this review is to summarize the current role of imaging in the assessment of patients with emphysema. The review will focus on CT for the evaluation of morphologic abnormalities and on the potential role for the evaluation of functional abnormalities and treatment targeting.