Background Lung cancer is an increasing problem in the older patient population due to the improvement in life expectation of the Western population. In this study we examine trends in lung cancer incidence and mortality in Denmark from 1980 to 2012 with special focus on the elderly. Material and methods Lung cancer was defined as ICD-10 codes C33-34. Data derived from the NORDCAN database with comparable data on cancer incidence, mortality, prevalence, and relative survival in the Nordic countries, where the Danish data were delivered from the Danish Cancer Registry and the Danish Cause of Death Registry with follow-up for death or emigration until the end of 2013. Results In 2012, about 50% of lung cancers were diagnosed among persons aged 70 years or more. For men and women older than 75 years the incidence rates have been increasing and for those aged 80-84 years, the rates have doubled since 1980. Due to the poor survival, similar trends were seen in mortality rates. Over the period, the one-year relative survival rates almost doubled in patients aged 70 years or more, but still only 25% of the patients aged 80-89 years survived their lung cancer for one year. Conclusion The incidence of lung cancer is closely linked to the pattern of tobacco smoking with the differences between gender and age groups reflecting smoking behavior in birth cohorts. Elderly patients with lung cancer are a heterogeneous group in whom treatment should be offered according to comorbidity and a geriatric assessment.