Two cases of intestinal-type adenocarcinoma of the renal pelvis (ARP) in 48- and 63-year-old females are presented. Both had a previous history of urinary obstructive disease, one secondary to staghorn calculus and the other to postirradiation stenosis following treatment for carcinoma of the cervix. Immunohistochemical findings revealed marked positivity to epithelial membrane antigen and focal positivity to cytokeratins and carcinoembryonic antigen. Chronic irritation of the renal pelvis plays an important role in the pathogenesis of ARP. In one of our cases of multicentric origin, the synergistic effect of pelvic irradiation and cyclophosphamide chemotherapy in a patient with a previous squamous cell carcinoma of the cervix, may be responsible for the pathogenesis of the ARP.