Introduction: CA (Carbohydrate Antigen) 19-9, CA125, and CA15-3 are well known tumor markers that commonly used in gastrointestinal, ovarian epithelial malignity and breast cancers, respectively. Particularly CA19-9 and CA125 levels are cited from time to time, and their prognostic importance are stressed more frequently. In our study, we compared serum CA19-9, CA125, and CA15-3 levels of our patients, those we follow with the diagnosis of bladder tumor, according to the features of the disease prospectively. Materials and Methods: Between March 2001 and June 2005, 61 patients that various therapies had been administered because of bladder tumor were included in the study, and 25 patients with benign prostate hyperplasia (BPH) complaining from hematuria initially selected as the control group. The patients with non-Transitional cell carcinoma bladder tumor (4/61) and with hematüria accompanying urinary infections or haemathologic problems (5/25) were excluded. Patients with bladder tumor were divided into two groups, as superficial and invasive groups. Each of the groups were compared individually and with controls in terms of CA19-9 (limit value; 37 IU/ml), CA125 (limit value; 35 IU/ml) and CA15-3 (limit value; 31 IU/ml). Stage, grade and number of focuses were evaluated as prognostic criterias. Independent t-test was used for statistical assessment. p<0.05 values were accepted as significant. Results: Transitional Cell Carcinoma (TCC) was present in 57 (74%) out of 77 patients who were included in the study. 21 (36.9%) of these were in the invasive group, and 36 (62.1%) were in the superficial group. Transurethral prostate resection was applied to 20 (26%) patients in the control group. Average ages of the tumor group and control group were 62.38±10.83 and 64.35±6.27, respectively and there were no statistically significant differences between these groups. When CA19-9, CA125 and CA15-3 levels of the tumor and control groups were compared, statistically significant differences were found in CA19-9 and CA15-3 levels. When comparison was performed in terms of prognostic factors, differences were observed in CA19-9 levels with regard to, size and grade of the tumor (p<0.05). There were no positive values detected for all the tumor markers in the control group. It was observed that CA19-9 was positive in 9 patients (15.7%), CA15-3 in 3 (5.7%), and CA125 in only 1 patient. Conclusion: We believe that carbohydrate antigens have limited efficiency and reliability in diagnosis and follow-up of bladder tumors and CA125 particularly has no place in the diagnosis of bladder tumor. In our study, finding positive results in some bladder tumor cases, suggests that CA19-9 and CA15-3 may have a diagnostic value and can be the indicators that demonstrate the presence of the tumor. Nevertheless, larger series are required for re-determining of the limit values, for urothelial tumors, cited in the literature.