The paediatric patient with end-stage lung disease has two donor options: size matched immature whole lungs or reduced-size mature lobes. The pool of donors of immature whole lungs is small. This makes reduced-size lung transplantation particularly appealing. This guide describes research and clinical issues relevant to reduced-size lung transplantation. Topics include clinical and investigative issues unique to this specialized discipline. Current thoughts on pulmonary preservation, the technique of experimental reduced-size lung transplantation and the ethical considerations of living donor lung transplantation are also reviewed.