BACKGROUND The study was conducted to compare lung transplantation outcomes between ABO-identical (AI) and ABO-compatible (AC) recipients. METHODS Charts of lung allograft recipients transplanted between February, 1990 and October, 1995 were reviewed. Standard triple-drug immunosuppression and general antimicrobial prophylaxis were provided. Surveillance spirometry was administered every three months. Flexible bronchoscopy (FB) with transbronchial biopsies (TBBs) were undertaken for clinical indications. Time to event analysis on acute (AR) and chronic (CR) rejection and actuarial survival were determined by Kaplan-Meier analysis. Cumulative curves were compared with a log rank test. Comparisons of age, maximum forced expiratory volume in one second (FEV1) in the single (SLT) and double (DLT) lung recipients, duration of intensive care unit and hospital stay were carried out using the Wilcoxon Rank Sum test. Gender, race, underlying diagnoses, cytomegalovirus (CMV) status and pulmonary reimplantation response (PRR) were compared by Chi-square or Fisher's exact test where appropriate. RESULTS Of the 100 lung recipients (age = 42.5 +/- 13.4 years; M:F = 50:50), 64 were AI and 36 AC. Median follow-up was 22 (range = 0-78) months. Outcome did not differ significantly between the 2 groups in terms of intensive care unit and hospital stay, PRR incidence and grade, incidence and frequencies of AR, median time and grade of first AR, maximum FEV1 for SLT and DLT recipients, incidence of CR and survival at 12 months. CONCLUSIONS As the donor supply remains limited, this could considerably simplify the logistics of future transplantation.