OBJECTIVES: Minimally invasive video-assisted thoracic surgery (VATS) was first introduced in the early 1990s. For decades, numerous non-randomized studies demonstrated advantages of VATS over thoracotomy with lower morbidity and shorter hospital stay, but only recently did a randomized trial document that VATS results in lower pain scores and better quality of life. Opposing arguments for VATS have always been increased costs and concerns about oncological adequacy. In this paper, we aim to investigate the cost-effectiveness of VATS. METHODS: The study was designed as a cost-utility analysis of the first 12 months following surgery and was performed together with a clinical randomized controlled trial of VATS versus thoracotomy for lobectomy of stage 1 lung cancer during a 6-year period (2008-2014). All health-related expenses were retrieved from a national database (Statistics Denmark) including hospital readmissions, outpatient clinic visits, prescription medication costs, consultations with general practitioners, specialists, physiotherapists, psychologists and chiropractors. RESULTS: One hundred and three VATS patients and 103 thoracotomy patients were randomized. Mean costs per patient operated by VATS were 103 108 Danish Kroner (Dkr) (€13 818) and 134 945 Dkr (€18 085) by thoracotomy, making the costs for VATS 31 837 Dkr (€4267) lower than thoracotomy (P < 0.001). The difference in quality-adjusted life years gained over 52 weeks of follow-up was 0.021 (P = 0.048, 95% confidence interval -0.04 to -0.00015) in favour of VATS. The median duration of the surgical procedure was shorter after thoracotomy (79 vs 100 min; P < 0.001). The mean length of hospitalization was shorter following VATS (4.8 vs 6.7 days; P = 0.027). The use of other resources was not significantly different between groups. The costs of resources were lower in the VATS group. This difference was primarily due to reduced costs of readmissions (VATS 29 247 Dkr vs thoracotomy 51 734 Dkr; P < 0.001) and costs of outpatient visits (VATS 51 412 Dkr vs thoracotomy 61 575 Dkr; P = 0.012). CONCLUSIONS: VATS is a cost-effective alternative to thoracotomy following lobectomy for stage 1 lung cancer. Economical outcomes as measured by quality-adjusted life years were significantly better and overall costs were lower for VATS. CLINICAL TRIAL REGISTRATION NUMBER: NCT01278888.