Urinary bladder paragangliomas are very rare, and the majority are hormonally active. Nonfunctioning paragangliomas are even rarer and more difficult to diagnose because of absence of catecholamine secretion. We present a 27-year-old woman with an asymptomatic paraganglioma of the urinary bladder discovered incidentally in a patient with prior resection of a functional pararenal paraganglioma. Metabolic profiles and cystoscopy were nondiagnostic. We demonstrate the increased sensitivity of 123I-MIBG SPECT/CT compared with planar scintigraphy for detection of a nonfunctional paraganglioma of the urinary bladder, which makes it valuable in evaluation of functional and nonfunctional paragangliomas.