Patients with cystic fibrosis (CF) have increased life span because of improved care over last 50 years. With increasing survival, predisposition of cancer may become evident. We have observed increase risk of gastrointestinal tract cancer, testicular cancer and lymphoid leukemia. Lung cancer in patients with CF is rare. Our patient developed chronic respiratory failure due to CF related bronchiectasis. Patient had progressive disease despite optimum treatment, requiring lung transplantation. Pathology of explant lung showed focus of invasive adenocarcinoma of lung origin. Patient had no evidence of lung carcinoma recurrence in one year. To our knowledge this is the fourth reported lung cancer case in a patient with CF.