Chronic obstructive pulmonary disease (COPD) and lung cancer are the leading causes of morbidity and mortality worldwide. Both diseases are associated with cigarette smoke exposure. Patients with COPD are at increased risk for the development of primary lung cancer, as well as poor outcome after lung cancer diagnosis and treatment. The causal relationship between COPD and lung cancer is not yet fully understood. However recent studies suggested the central role of chronic inflammation, induction of oncogenic pathways, and epigenetic alterations. At present a lung cancer patient with concomitant COPD should be treated based on the current lung cancer treatment guidelines. In case of an early stage lung cancer, curative intent therapy such as an anatomic lobar resection is the best therapeutic option. However reduced pulmonary functions are usually a challenge for optimal therapy of lung cancer. Preoperative functional status must be optimized with appropriate medical therapy, pulmonary rehabilitation and smoking cessation.