Self-expanding metallic stents were inserted into the ureters of two female patients (29 and 46 years old) with malignant ureteric stenosis, in the first patient caused by metastases of a malignant melanoma, in the second by retroperitoneal lymph-node metastases from a colon carcinoma. In the first patient the stent was introduced antegrade into the left ureter via a nephrostomy after balloon dilatation of the stenotic segment. She was subsequently without symptoms, but six weeks later the ureter got kinked just above the bladder due to continued tumour growth against the stent. After insertion of a silicon splint she had no further symptoms referrable to the kidneys until she died two months later. In the other patient in whom both ureters were obstructed they could not be catheterized percutaneously. Stents were, therefore, introduced transurethrally after previous balloon dilatation of the stenoses. Obstruction occurred in the right ureter three days after the procedure due to mucosal oedema, but it was controlled by anti-inflammatory drugs. Hydronephrosis developed again six months later, caused by circumscribed incrustations in parts of the the stent not covered by mucosa. Silicon splints were placed bilaterally and the patient has so far been free of symptoms for two months.