Objectives: To study the histopathologic changes in the urinary bladder associated with Double-J (DJ) stenting and the correlation between these changes and the period of stenting.Methods: In a 2-year period, a retrospective study was carried out on 30 patients indicated for DJ stenting. These patients underwent cold-cup cystoscopic biopsies from the ipsilateral ureteral orifice at the time of removal of DJ stents.Results: The mean age of the 30 patients included in our study was 43.6 +/- 8.6 years (range 26-74 years). The stent size used was 4.7 and 6F. The stent duration was 2 weeks in 2 patients, 4 to 6 weeks in 18 patients, 6 to 12 weeks in 6 patients, and more than 12 weeks in the remaining 4 patients. Stent placement was optimum in all patients. The histopathologic study of 30 biopsies showed mild, acute eosinophilic inflammatory reactions with edema in patients with stenting less than 14 days. Acute lymphocytic eosinophilic cystitis with edema was found with stents of 2 to 6 weeks. Brunn's nests were reported with stents more than 6 weeks. Cystitis cystica was seen in those who had stents more than 12 weeks.Conclusions: Our study shows that acute and chronic allergic inflammatory changes can be seen around the bladder coil of the DJ stents. It is of major importance for the urologist to limit the use of DJ stents to highly indicated cases only and for a short interval.