Objective To investigate the expressions of PTEN and MDM2 in bladder transitional cell carcinoma (BTCC) and their clinical significance.Methods The expressions of PTEN and MDM2 were detected by tissue immunohistochemistry test (SP method) in BTCC (n =80) and normal bladder tissues (n =20).The relationship between PTEN and MDM2 as well as their correlations with clinical pathological features were analyzed.Results The positive rate of PTEN in different pathological grading (G1,G2,G3)and clinical staging [superficial (Tis ～ T1),infiltration (T2 ～ T4)] was (86.20％,74.07％,37.50％ ;80.00％,46.67％),respectively,with a significant difference (x2 =15.004,P ＜ 0.01 ; x2 =9.497,P ＜0.01).The positive rate of MDM2 in different pathological grading(G1,G2,G3) and clinical staging [superficial (Tis ～ T1),infiltration (T2 ～ T4)] was (82.75％,55.55％,37.50％ ; 70.00％,43.35％),respectively,with a significant differcnce(x2 =11.543,P ＜ 0.01 ; x2 =5.556,P ＜ 0.05).The expression of PTEN was negatively correlated with that of MDM2 in BTCC (r =-0.611,P ＜ 0.05).Conclusions Expressions of PTEN and MDM2 might be involved in the BTCC pathogenesis.The combined detection of PTEN and MDM2 might be of great value in the prediction of tumor behavior and prognosis.