A 70-year-old male patient with diabetes mellitus presented to our hospital with acute obstructive non-oliguric renal failure. Abdominal CT revealed obstructive hydronephrosis and irregular thickening of the bladder wall. Upon cystoscopy, samples of tissue were taken and found to be positive for Aspergillus spp. on histology, indicating infection of the bladder wall. The patient was treated successfully by means of a percutaneous nephrostomy and a 30-day course of caspofungin.