To determine the prevalence of hyperhomocysteinemia (plasma homocysteine[Hcy] concentration≥15 μmol/L) and evaluate its correlation with allograft function.The study included 159 stable renal transplant recipients (104 men and 55 women). The prevalence and severity of hyperhomocysteinemia were compared in the transplant recipients vs 72 patients (48 men and 24 women) receiving hemodialysis therapy.The mean (SD; range) fasting total Hcy concentration was higher in the hemodialysis group compared with the renal transplantation group: 27.4 (18.3; 10-95) μmol/L vs 16.6 (9.5; 4.5-45.0) μmol/L (P=.00). Hyperhomocysteinemia occurred more frequently in patients receiving hemodialysis therapy (74% vs 49%). No significant correlation was observed between Hcy concentration and recipient sex, cyclosporine trough concentration and concentration at 2 days after dosing, dyslipidemia,cytomegalovirus infection, diabetes mellitus, or aspartate or alanine aminotransferase concentration. Multivariate regression analysis revealed that serum creatinine concentration (P=.02) was the major determinant of increased total Hcy concentration in renal transplant recipients.A high prevalence of moderate hyperhomocysteinemia was observed in renal transplant recipients. There was no correlation between graft function and Hcy concentration.