OBJECTIVE: In 1998 The Danish Lung Cancer Group published the first edition of guidelines for diagnosis and treatment of lung cancer. A national registry was implemented in the year 2000 with the primary objective to monitor the implementation of these guidelines and nationwide to secure and improve the quality of the clinical management of lung cancer. The results of this effort are reported with special focus on surgery. METHODS: Through systematic nationwide registration a total of 24,153 patients have been included in the period 2000-2007. Indicators describing staging, surgical procedures, complications and survival have been registered in those 5007 patients who underwent surgery. Using an Internet based closed circle with a safe program (firewall and encryptation) more than 95% of this subgroup of patients have been notified. Each year the results have been audited locally, regionally and nationally and improvements have been proposed, implemented, monitored and consecutively evaluated by the audit-plenary. RESULTS: This strategy has been a contributory factor to significantly improve the results in mortality, survival and surgical procedures. Thus, the 30-days mortality following surgery has decreased from 5.2% to 3.6% and survival has increased from an overall 1- and 2-year survival of 69% and 50% in 2000 to 77% and 60% in 2007, respectively. A number of other key indicators were also improved: the lobectomy rate has increased from 54% to 73% and the pneumonectomy rate has decreased from 23% to 11%. The proportion of patients having surgery within 14 days from referral has increased from 69% to 87%. CONCLUSIONS: Establishment of a national lung cancer group with the primary tasks to implement updated national guidelines and to secure valid registration of clinical baseline data and quality parameters has been a contributory factor to significantly improve the quality of lung cancer surgery.