Abstract: Objective: To study the expression of X-linked inhibitor of apoptosis protein(XIAP) in bladder transitional cell carcinoma(BTCC) and to clarify the relationship between the pathological grades and clinical stages of BTCC.Methods: The epithelium speciment of 62 cases of BTCC confirmed by pathological method were collected and the expression of XIAP was detected by using immunohistochemical assay(SP methods).Results: The positive expression rate of XIAP in BTCC was 67.7%,which was significantly higher than that of normal bladder tissues(23.1%)(P<0.005).The positive expression rates in grade Ⅰ,Ⅱ and Ⅲ were 75.0%,57.9% and 66.7%,respectively;The positive expression rates in stage Ta-T1 and T2-T4 were 63.9% and 73.1%,respectively.Conclusions: It is suggested that high expression of XIAP may play an important role in the mechanisms of tumorignesis and development of BTCC.