Abstract: Objective　To investigate the relationship between E-c adherin(E-cad)expression and histopathological grade,tumor stage and the other biological behavior in transitional cell carcinoma of urinary bladder.Me thods　Immunohistochemical streptavidin-peroxidase method(SP) was emplo ye d using a mouse monoclonal antibody for human E-cad(HECD-1)to stain serial sna p-frozen sections of 10 normal bladder and 28 TCC specimens. Results E-cad expression was normal in 50%(14/28) of TCCs versus in 100%(10/10)o f normal bladder specimens(P<0.01).Abnormal expression of E-cad was signif icantly correlated with grade and stage of TCC,26.3%(5/19) of grade Ⅰ and grad e　Ⅱ TCCsshowed abnormal E-cad expression compared with 100%(9/9) of grade Ⅲ TCCs(P<0.001),abnormal expression was found in 87.5%(7/8) of invasiv e TCCs compared with 35%(7/20) of superficial TCC(P<0.05).The differences were not statistically significant betwe en initial tumor with recurrent tumor and solitary tumor with multifocal tumor ( P>0.05).All of 14 TCCswith abnormal E-cad expression displayed heterogen eous staining, completely negative TCC had not been observed. Conclusion 　E-cad expression in normal bladder transitional epithelia was preserved whe reas TCC showed a reduction of E-cad expression.Decreased E-cad expression was associated with both increased grade and stage of TCC.E-cad expression didn't c orrelate with the number of TCC,no difference was found between initial TCC with recurrent TCC.