Abstract: Background and Objective: CD14 is a molecule involved in non-specific immunity that plays important roles in immune cell activation and signaling in response to bacterial cell wall derived components. The current study aimed to determine the diversity of bacterial infection in urinary bladder tumours and studying the immunoexpression of CD14 in bladder tissues associated with bacterial infection. Materials and Methods: In total, 65 patients with bladder tumours with urine and paraffin embedded tissue samples were enrolled in the study, among these patients, 50 had bladder carcinoma (BC) and 15 had benign tumours (BT). Specific culture media and biochemical tests were used to isolate and identify bacterial species and immunohistochemistry (IHC) was used to detect CD14 tissue expression in both groups. Chi-square test was used to compare the difference between percentages of this study by using SAS. Results: The results showed that 37 out of 50 BC patients were positive for gram-negative bacteria, 3 out of 50 patients were positive for gram-positive bacteria and 10 out of 50 patients were negative growth. All BT patients showed presence of gram-negative bacteria. IHC staining showed that CD14+ was significantly over expressed in BC patients compared with BT patients (82% vs. 46.7%, p< 0.01). CD14 expression was also high in gram-negative bacteria infected bladder tissues in patients with both BC and BT and its expression was significantly correlated with this type of bacterial infection (p<0.01). Conclusion: A significant association between CD14 expression and bacterial infected tissues was found and concluded that CD14 activation driven by microbial inflammation probably contributes to bladder cancer.