Interstitial pneumonia is well known to increase the risk of lung cancer. We describe a young man who underwent single-lung transplantation for confirmed usual interstitial pneumonia and who was unexpectedly found to have multifocal adenocarcinoma in the explanted lung. Induction immunosuppression therapy was decreased and full screening for further tumor development was undertaken. Post-operatively further consolidative changes developed in the remaining native lung and, after diagnosis and staging, a native pneumonectomy was performed for adenocarcinoma. The good early outcome and management dilemmas are discussed, together with a review of the literature.