Lung transplantation, single or bilateral sequential, is the final option for patients with emphysema. This study analyzed the outcome of lung transplants for emphysema (single or double), and evaluates the incidence, predictive factors and prognosis of lung hyperinflation (LHI) in unilateral transplants. We prospectively studied patients undergoing lung transplantation for emphysema. On admission to the Intensive Care Unit (ICU) and at 12, 24, 48 and 72 h we tested the patients' respiratory function, oxygen arterial pressure (PaO2) and mean pulmonary arterial pressure (MPAP) before transplantation. LHI incidence, duration of mechanical ventilation and hypoxemia, ICU stay and mortality was also analyzed. We studied 34 consecutive patients undergoing lung transplantation for emphysema, 14 single and 20 bilateral. Single-lung transplantation had a higher mortality (50%) than double-lung transplantation (11%), with an odds ratio of 9.0 (1.3-48.7). Of the 14 patients who received a single graft, 9 patients (64%) developed LHI. No predictive factors for LHI could be established. Duration of mechanical ventilation (22 vs 3 days) and ICU stay (36 vs 6 days) was much longer in patients with LHI; however, only ICU stay reached statistical significance (P = 0.011). Mortality in patients with LHI was higher, 67% vs 20% (NS). We conclude that single-lung transplant in emphysema patients has a worse prognosis than bilateral transplant, with a 9-fold higher mortality rate. LHI is a common event in single-lung transplant for emphysema and is associated in our patients with a longer stay at the ICU.