The limited number of suitable lung donors is the major obstacle to clinical application of lung transplantation. The "twinning procedure" may represent one strategy to optimize the use of the small pool of available grafts. From November 1991 to May 2003, 99 single lung transplants (SLTx) were performed including 46 (46%) cases of the "twinning procedure." We divided the study population into two groups: group A (recipients of the "first" lung) and group B (recipients of the "second" lung). The ischemia time was significantly different (A: 216 +/- 48 minutes, B: 310 +/- 89 minutes, P <.001). Differences were not observed in the incidence of graft failure (A: 2, B: 0, P = NS), in the length of mechanical ventilation (A: 12.8 +/- 29.4 days, B: 7.8 +/- 15.2 days, P = NS), or ICU stay (A: 18.8 +/- 50.6 days, B: 15.2 +/- 17.1 days, P = NS), or of hospitalization (A: 37.8 +/- 56.8 days, B: 31.4 +/- 31.7 days, P = NS). Three bronchial anastomotic complications occurred in each group. The incidence of infections (A: 0.015 events/patient/month, B: 0.011 events/patient/month, P = NS) and of treated acute rejections (A: 0.011 events/patient/month, B: 0.011 events/patient/month, P = NS) was similar in the two groups. One-year survival rates were 86% +/- 7% and 72% +/- 10% in group A and B patients, respectively (P = NS). In our experience the different ischemia times related to the twinning procedure did not increase the mortality or morbidity in the early and midterm period.