Since most patients with cystic fibrosis (CF) die from respiratory failure, lung transplantation remains for many of them the ultimate treatment. The decision to put a patient on the transplantation waiting list is based on a list of criteria from international guidelines. We aimed to determine if a survival score could help determine when a CF patient has to be referred to a transplantation program. We applied this score to a small number of consecutive patients from our adult CF clinic, but found that it was of limited value for individual decision. Awareness of international guidelines and clinical judgement are essential to refer CF patients at proper time for lung transplantation.