Objective To observe the efficacy and safety of prednisone combined with leflunomide in the treatment of immu-noglobulin A(IgA)nephropathy.Methods Eighty patients with IgA nephropathy were selected and divided into the treatment group and control group.The patients in the control group were given prednisone and the treatment group received prednisone plus leflunomide.The treatment course lasted for 12 months.Total effective rate,serum creatinine(Scr),urinary protease inhibitor C(Cys C),blood urea nitrogen(BUN)and 24 h proteinuria(U-prot)were measured at 6-month and 12-month treatment.Serum levels of vascular endothelial growth factor(VEGF)and endothelin-1(ET-1)were measured by enzyme-linked immunosorbent assay (ELISA).Results The effective rates at 6-month and 12-month treatment in the treatment group were 85% and 90% respective-ly,which in the control group were 65% and 70% respectively,the difference between the two groups was statistically significant (P<0.05).The BUN and U-prot levels after 6-moth and 12-month treatment were significantly reduced,moreover the effect in the treatment group was better than that in the control group(P<0.05).The levels of plasma VEGF and ET-1 after 6-moth and 12-month treatment in the two groups were decreased,moreover the decrease range in the treatment group was greater than that in the control group(P<0.05).Conclusion Prednisone combined with leflunomide can significantly improve the renal function in the pa-tients with IgA nephropathy,and it is safe and effective.