Surgery is generally considered to be the treatment of choice for anatomically localized non-small-cell lung cancer, but its effectiveness remains unproven. Observational studies have been of limited value because the criteria by which patients are selected for surgery create substantial differences between patients who undergo surgery and those who do not. One small randomized trial of surgery vs radiotherapy was inconclusive, but several large trials of lung cancer screening have provided indirect evidence against a benefit from surgery. Two ongoing randomized trials, one on extensive vs limited resection and the other on the effect of surgery in more extensive disease, may provide further insight into the effectiveness of surgery in the treatment of localized non-small-cell lung cancer. Development of a large randomized trial to directly assess the effectiveness of surgery in the treatment of localized non-small-cell lung cancer has been precluded by ethical concerns, but may need to be reconsidered if indicated by the findings of the two ongoing studies.