A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether lung volume reduction surgery (LVRS) might be superior to medical treatment in the management of patients with severe emphysema. Overall 497 papers were found using the reported search, of which 12 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results are tabulated. We conclude that LVRS produces superior patient outcomes compared to medical treatment in terms of exercise capacity, lung function, quality of life and long-term (>1 year postoperative) survival. A large proportion of the best evidence on this topic is based on analysis of the National Emphysema Treatment Trial (NETT). Seven studies compared LVRS to medical treatment alone (MTA) using data generated by the NETT trial. They found higher quality of life scores (45.3 vs. 27.5, P<0.001), improved maximum ventilation (32.8 vs. 29.6 l/min, P=0.001) and lower exacerbation rate per person-year (0.27 vs. 0.37%, P=0.0005) with LVRS than MTA. Mortality rates for LVRS were greater up to one year (P=0.01), equivalent by three years (P=0.15) and lower after four years (P=0.06) postoperative compared to MTA. Patients with upper-lobe-predominant disease and low exercise capacity (0.36 vs. 0.54, P=0.003) benefited the most from undergoing LVRS rather than MTA in terms of probability of death at five years compared to patients with non-upper-lobe disease (0.38 vs. 0.45, P=0.03) or upper-lobe-disease with high exercise capacity (0.33 vs. 0.38, P=0.32). Five studies compared LVRS to MTA using data independent from the NETT trial. They found greater six-minute walking distances (433 vs. 300 m, P<0.002), improved total lung capacity (18.8 vs. 7.9% predicted, P<0.02) and quality of life scores (47 vs. 23.2, P<0.05) with LVRS compared to MTA. Even though LVRS has a much greater cost per person over five years ($137,000 vs. $100,200, P<0.001), its improved lung function, greater exercise capacity and better quality of life scores make it a preferable treatment option to MTA, with particular indications for patients with upper-lobe-predominant disease and low exercise capacity.