Potentially operable patients with Stage I non-small cell lung cancer who were treated with stereotactic ablative radiotherapy (SABR) between 1993-2010 were retrospectively identified in a prospectively collected database. Despite the median age of 76 years and the median comorbidity score of 2 in these 177 potentially operable patients, the 3-year survival was 85%. Post-SABR 30-day mortality was 0%, while predicted 30-day mortality for a lobectomy, derived using the Thoracoscore predictive model, would have been 2.6%. Local control at 3 years was 93%.