The malignant urothelial tumors of the urinary bladder represent 95% of the malignant tumors of this organ.Aim of the work: is to evaluate the expression of cyclooxygenase-2 (COX-2) in the precancerous and malignant epithelial tumors of the bladder and its correlation with the different prognostic factors.Material and methods: this study included 60 bladder carcinoma specimens obtained by radical cystectomy and 5 control bladder specimens from the mucosa away from the tumors.Results: there was no statistically significant relationship between COX-2 expression and most of the different clinico-pathological factors while there was statistically significant relationship between COX-2 expression and the stage of the tumors.Conclusion: there was statistically significant relationship between COX-2 expression and the stage of the tumors. Further studies are needed to determine the possibility of considering COX-2 expression in the malignant bladder tumors as a prognostic factor.