BACKGROUND Kidney transplantation is associated with an increased risk of tumors in the urinary bladder. Among all the pathological types of tumors in the bladder, paraganglioma, which arises from extra-adrenal paraganglia and consists of chromaffin cells, is rare. Paragangliomas might cause severe clinical symptoms due to catecholamine hypersecretion or mass compression. Bladder paragangliomas are rare, especially those appearing after kidney transplantation. Here, we report a case of bladder paraganglioma developing after kidney transplantation. METHODS A 63-year-old woman received a kidney transplant 12 years ago and took oral immunosuppressants (cyclosporine, mizoribine, and methylprednisolone) for regular post-transplant treatment. The patient felt no discomfort and she came to the hospital for a routine checkup. A mass located in the bladder was incidentally discovered by computed tomography, and she underwent surgical treatment. A 2 cm × 2 cm invasive mass was found in the trigone of the bladder and the mass was removed. The diagnosis of paraganglioma was confirmed by morphology and immunophenotyping. The patient had a good prognosis and is still alive. CONCLUSIONS Paraganglioma can grow in the bladder, which might cause no clinical symptoms. The diagnosis mainly depends on morphology and immunophenotyping. Surgical resection is an important treatment option for such patients.