Purpose: In this study, we investigated the ability of UroVysion™ to assess response to intravesical therapy in patients with high risk superficial bladder tumors. Materials and methods: We performed a retrospective review of patients undergoing intravesical therapy for high risk superficial bladder tumors. Urine specimens were collected for UroVysion™ analysis before and immediately after a course of intravesical therapy. Cytology and cystoscopy were performed six weeks after treatment, using either a positive cytology or visible abnormality on cystoscopy as a prompt for biopsy. The operating characteristics of the UroVysion™ test were then determined. Results: 41 patients were identified in whom 47 cycles of induction and 41 cycles of maintenance intravesical therapy were given during the study period. This yielded a total of 88 treatment and evaluation cycles. Median follow-up was 9 months per induction (range 1-21 months) and 13 months per patient (range 1-25 months). A total of 133 urine samples were collected for UroVysion™ of which 40 were positive. Based upon standard clinical evaluation, 41 biopsies were performed which detected 20 recurrences. UroVysion™ testing performed immediately upon completion of therapy for the 41 patients undergoing biopsy yielded a sensitivity, specificity, and accuracy of 85%, 61%, and 71%. Conclusions: The use of UroVysion™ following intravesical therapy for high-risk superficial bladder tumors helps to identify patients at high risk of refractory or recurrent disease who should undergo immediate biopsy under anesthesia.