Objectives. To review diagnoses of nephrogenic adenoma and in particular to evaluate its association with transitional cell carcinoma (TCC) of the bladder and its relationship to renal transplantation. Methods. A retrospective review of 22 cases of nephrogenic adenoma (NA) diagnosed between 1989 and 1996 was conducted, 7 of which were in renal transplant patients. Data collected in each case included demographic details, predisposing factors, associated urologic pathology, mode of presentation, cystoscopic finding, management, and follow-up. Results. There was a 3:1 predominance of men. Mean follow-up was 21.4 months (range 3 to 50). Six patients (27%) had one or more recurrences. All 22 patients had some form of previous bladder insult or surgery, including recurrent urine infections, urinary tract instrumentation, placement of ureteric stents, cystodiathermy, and open bladder surgery. Six cases were associated with TCC of the bladder, of which 4 had NA lesions directly over or close to the site of previous fulguration. In 4 patients, there was a temporal relationship between the administration of intravesical doxorubicin hydrochloride or bacille Calmette- Guerin (BCG) and the onset of NA lesions. One case was associated with an inverted papilloma that had not been described before. In 7 renal transplant cases, 3 lesions were found contralateral to the side of the ureterovesical anastomosis. All 22 cases were benign histologically, but one NA was found within a low-grade bladder TCC. Nineteen cases were followed up regularly with no malignant transformation. Three patients were lost to follow-up. Conclusions. This study has demonstrated an association between NA and bladder cancer. Patients with NA, especially those treated with intravesical chemotherapy or BCG, should have regular cystoscopies. Fulguration or transurethral resection appear to be sufficient treatment. No renal transplant patients had vesical TCC and NA simultaneously. Neither immunosuppression nor ureterovesical anastomosis appeared to be a significant predisposing factor in the transplant patients.