BACKGROUND: Although transplantation is the best treatment for many people with end-stage renal disease, the gap between the number of organs and the number of potential recipients continues to widen. In addition to living-related individuals, the primary source of donor kidney, the severe organ shortage has led to consideration of genetically unrelated but emotionally related persons as donor candidates. The aim of this study was to compare the results of spousal kidney transplantation with those of living-related kidney transplantation and to analyze the characteristics of spousal kidney transplantation. METHODS: Clinical data were retrospectively analyzed from 21 patients with spousal kidney transplantation and 205 patients with living-related kidney transplantation. Cumulative renal allograft survival was compared between the two groups using Kaplan-Meier curve and log-rank test. Subgroup analysis was done within the patients with spousal kidney transplantation. RESULTS: The patients were significantly older in spousal group (43.7+/-7.8 years) than in living-related group (36.2+/-10.8 years). Donor age was also significantly higher in spousal group (43.0+/-8.4 years) than in living-related group (39.8+/-13.9 years). The number of HLA mismatch was significantly larger in spousal group (3.79+/-1.03) than in living-related group (2.60+/-1.21). The episodes of acute rejection occurring within a year after the transplantation were more frequent in spousal group (5/21) than in living-related group (13/205). Kaplan-Meier curves for cumulative survival of renal allograft revealed no difference between spousal group and living-related group. Renal allograft survival rates in spousal group were 85.2% at 1 year, 75.2% at 5 years, and 67.7% at 10 years after the transplantation. In living-related group, renal allograft survival rates were 96.6% at 1 year, 85.9% at 5 years, and 69.9% at 10 years after the transplantation. Within the patients with spousal kidney transplantation, cumulative renal allograft survival was superior in cases with absent acute rejection, husband-to-wife transplantation, and the number of HLA mismatch less than 5. CONCLUSION: Spousal kidney transplantation shares comparable results with living-related kidney transplantation despite older age, poorer HLA matching and a higher rate of acute rejection. Spousal donor transplants could be a real alternative especially when the donors are husband and the number of HLA mismatch is less than 5.