We reviewed the clinical course and pathologic findings of 17 patients with adenocarcinoma of the urinary bladder at Massachusetts General Hospital between 1962 and 1978. The 12 men and 5 women were between thirty-eight and eighty-six years old (mean, sixty years). Five patients had urachal adenocarcinoma, 8 had pure adenocarcinoma, and 4 had mixed adenocarcinoma and transitional cell carcinoma. Twelve of 17 patients (71 per cent) had muscle invasion (T2-T3), and none had evidence of regional or distant metastases at initial presentation. The mean follow-up was four years. The treatment modalities included transurethral resection alone in 3 patients, radical cystectomy in 4, simple cystectomy in 2, salvage radical cystectomy in 1, and partial cystectomy in 7, 3 of whom also received radiation therapy. Over-all crude three and five-year survival rates were 60 per cent and 27 per cent, respectively; patients with invasive disease did poorly regardless of treatment modality. Five of 8 patients who died had evidence of metastatic disease, and only 1 patient with invasive disease was alive more than five years. However, 2 of 3 patients with invasive urachal adenocarcinoma who had preoperative radiotherapy plus partial cystectomy are free of disease at thirty-eight and sixty months.