BACKGROUND The outcome of renal transplantation in patients with IgA nephropathy (IgAN) may be affected by recurrence of the original disease. Despite this risk of recurrent glomerulonephritis, graft survival in patients with IgAN is considered good although formal comparisons with graft survival in patients with other renal diseases have given conflicting results. METHODS We have studied both recurrence rate and outcome after renal transplantation in 79 adult patients with IgAN, all of whom received a first renal graft (55 cadaveric, 24 living-related donor) in our center in the period between 1969 and 1997. Graft survival in patients with IgAN was compared with the outcome in patients with pyelonephritis and adult polycystic kidney disease (group 2) and patients with non-IgA primary glomerulonephritis (group 3). RESULTS Follow-up averaged 5.6 +/- 4.5 years. Histological evidence of mesangial IgA deposits was present in 17 of 32 available biopsies (53%). Clinically recurrent IgAN was diagnosed only in 7 patients (9% of all recipients), with a higher incidence in recipients of a living-related donor graft (5/24 (20%) vs 2/55 (4%)). These recurrences were diagnosed in biopsies taken 13-145 months after transplantation; and all were characterized by significant proteinuria (> 1 g/day). In only one patient the graft was lost due to the recurrence. For recipients of a cadaveric graft, the 5-year graft survival was significantly better in IgAN patients than in both reference groups (86% vs 67% in group 2; p = 0.012, and 60% in group 3; p = 0.007). This difference remained significant after censoring for death. There was no statistically significant difference in the patient survival between the groups. The rejection rate in the first 3 months was numerically lower in the IgAN patients (37% vs 43% and 49%, respectively). and total immunological failure rate was also lower in the IgAN patients compared to the control groups (13% vs 21% and 23%, respectively); although the differences were not statistically significant. The 5- and 10-year graft survival in recipients of living-related donor grafts was significantly better in IgAN patients than in group 3 (96% and 84% vs 64% and 21%, respectively; p = 0.02), but similar to graft survival in group 2 (87% and 75%). CONCLUSIONS A clinical recurrence of IgAN occurred in 4% of patients with a cadaveric donor graft and 20% of patients with a living-related donor graft. The recurrence had negligible influence on 5- and 10-year graft survival. Graft survival after cadaveric transplantation was better in the IgAN patients compared to control groups; possibly due to the lower immunological failure rate in IgAN.