Background: Bladder cancer is a common malignancy in Egypt and other developing countries in which infection with Schistosoma haematobium is prevalent. Bladder cancer caused by bilharziasis has different clinical and biological characters than that observed in the western world. In this study, we used the TRAP technique to estimate telomerase activity in bilharzial bladder cancer specimens and we correlated the findings with other clinical and pathological findings. Patients and methods: Bladder cancer specimens were obtained from 57 patients who underwent radical cystectomy and pathological diagnosis was obtained in all patients. Tissue samples were frozen in liquid nitrogen and stored at -80 degrees C. Telomerase activity by PCR-ELISA technique was measured using TRAP technique. Results: Our patient group included 45 males and 12 females with a median age of 49 years. The majority of our patients (35/57) have squamous histology and they have proven bilharzial history shown in the pathology specimens. Stage P3b was encountered in 29/57 patients whereas thirty-five patients have grade II tumors. The majority of our patients (41/57) were negative for pelvic nodes metastases. Telomerase activity was detected in 27/57 patients (47.4%). The mean level of telomerase was 0.85+/-0.77 in positive patients and 0.029+/-0.025 in negative patients. The expression of telomerase and its mean level in patients above age of 60, in males and in those with squamous pathology, higher grade of tumors or positive node was higher than those without but the difference did not reach statistical significance (P>0.05). Alternatively, expression was significantly higher in those with stages (P1-P3a) compared with P3b-P4a disease stages (66.6% vs. 37.1, P=0.03). Conclusion: Telomerase activity is increased in bilharzial bladder cancer although to a lesser degree than that reported for TCC in the western world, which could be explained, by different biological behavior or different assay methods. Further larger studies with more number of patients are still needed to determine its potential value for early detection and possible use as a therapeutic target.