Abstract: Objective: To detect the expression of E2F3 and c-Myc proteins in bladder transitional cell carcinoma (BTCC) tissue and normal bladder epithelial tissue and to analyze the correlation of E 2F3 and c-Myc expression with the bi -ological behaviors of BTCC. Methods:Immunohistochemistry was used to detect the expression of E 2F3 and c-Myc in BTCC tissue (n=64) and normal bladder mucosa ( n=10). Immunohistochemical results were analyzed with Image-Pro Plus software and the corresponding results were reported as integrated optical densities (IOD). Results: The expression of E2F3 and c-Myc in BTCC tissue was higher than that in normal bladder mucosa. The expression of E2F3 and c-Myc was correlated with pathological grade and clinical stage (P<0.05, P<0.01; P<0.01, P<0.01). Immunohistochemistry indicated that the IOD of E 2F3 and c-Myc in BTCC tissue was significantly higher than that in normal bladder mucosa ( P<0.01, P< 0.01). E 2F3 expression was correlated with c-Myc expression ( P<0.01). Conclusion:E2F3 and c-Myc protein levels can be used as diagnostic and prognostic indices of BTCC. This study provides a primary theoretical basis for gene target therapy of BTCC.