OBJECTIVE To access the safety and effectiveness of Double-J-stents in treating symptomatic hydronephrosis during pregnancy. METHODS From 1994 to 1999, 21 women were hospitalized in the Urology Clinic at the University Hospital of Crete. Fourteen patients presented acute pyelonephritis, six painful hydronephrosis and one spontaneous renal rupture. In four cases the hydronephrosis was caused by calculus in the upper 3rd quadrant of the ureters. In 13 out of 14 cases of urinary febrile infection and one with spontaneous renal rupture, the dilatation resulted from direct compression of the ureters by the gravid uterus. Using ultrasound guidance, 21 ureteral stents were successfully placed under local ane- sthesia. RESULTS In 14 out of 21 patients with urinary infection, we observed remission of fever during the first 24 hours after the placement of the ureteral stents. In the patient with spontaneous renal rupture the remission of symptoms was observed a few hours after the ureteral drainage. Complications were reported in six cases, such as, voiding symptoms and discomfort. CONCLUSIONS Double-J-ureteral stenting is an effective, simple and safe method in treating symptomatic hydronephrosis during pregnancy.