Pulmonary transplantation remains the ultimate therapeutic option for selected patients with an advanced pulmonary disease and terminal respiratory insufficiency when all other therapeutic options have been exhausted. The optimal time-frame to proceed to a first discussion and evaluation about lung transplantation may be difficult to determine. This article describes the pathway of a patient towards lung transplantation and summarizes the criteria, which may help to timely identify eligibility for this therapeutic modality. We will focus mainly on the 2021 update of the International Society for Heart and Lung Transplantation (ISHLT) recommendations for the selection of lung transplant candidates.