Lewis X antigen in bladder cancer patients can be found in urine. In order to determine the presence of Lewis X antigen in exfoliated cells from voided urine, also cytopathologic examination and bladder ultrasound were detected in bladder cancer patients. Totally 42 patients were included in the study. Voided urine samples were obtained for immunocytology of Lewis X and cytopathology. Bladder ultrasound and cystoscopy were performed. Bladder tumors were diagnosed in 13 patients. False-negative results were seen in small, superficial and low grade tumors. Both cytopathology and bladder ultrasound increased the sensitivity. Immunocytology of urine sample for the Lewis X antigen is a sensitive method for noninvasive detection of transitional cell tumors.