The plasma nitric oxide (NO) in 32 patients with renal allografts was observed before transplantation and in the early period of three months after transplantation. Endothelin (ET), cyclosporin A blood concentration, Creatinine (Cr), blood urea nitrogen (BUN) were measured simultaneously. The results showed that plasma NO level (24.01 +/- 1.15 mumol/L) before transplantation was significantly higher than that after transplantation. There was significant correlation between plasma NO level and ET, Cr, BUN and blood pressure. We consider that plasma NO concentration may reflect the function of renal transplant and play an important role in early renal injury after kidney transplantation.