Objective：To study the intrarenal expression of Fas ligand （FasL） and T cell intracellular antigen-1 （TIA-1） protein during acute rejection after renal transplantation. Methods： Immunohistochemical technique was used to detect FasL and TIA-1 expression in 32 transplanted renal samples,2 living donor kidneys and 8 adjacent samples of renal cancer （including 14 acute rejection samples, 15 chronic and 13 non-rejection ones according to Banff criteria）. Results： The positive FasL staining was observed mainly in cytoplama of renal tubule epithelia,and the positive rate was significantly higher in acute rejection samples than in others（P〈0.01 ）. TIA-1 was found in both tubular epithelial cells and interstitial infiltrating lymphocytes,occasionaly in small arterial endothelial cells. The positive staining rate of TIA-1 acute rejection samples was also higher than those of other samples（P〈0.05）. The expression of FasL and TIA-1 in acute rejection samples was positively correlated with the severity of tissue damages. Conclusion： Over expression of FasL and TIA-1 in acute rejection renal allograft tissues may indicate the activation of T cells,and its detection may be helpful for early diagnosis of acute rejection