Purpose: We evaluated clinical outcomes after attempted prenatal intervention in fetuses with hydronephrosis. Materials and Methods: We retrospectively reviewed the histories of 10 fetuses considered for prenatal intervention between 1984 and 1993. One female and 8 male fetuses had bilateral hydroureteronephrosis and profound or progressive oligohydramnios, and 1 male fetus had massive progressive unilateral hydronephrosis. Results: Shunt placement was not recommended and it was refused by the parents in 1 case each. Amniotic shunting was attempted in 8 fetuses between 22 and 28 weeks of gestation. Shunts were successfully placed with decreased hydronephrosis and increased amniotic fluid volume in 4 cases, while shunt placement was not technically possible in the remainder. Two shunts that retracted intra-abdominally at birth required laparotomy for retrieval. Postnatally all patients with shunts had compromised renal function. Of the 4 patients in whom attempts were unsuccessful 3 had mildly diminished renal function and 1 died of nonrenal causes (intra-abdominal sepsis) on day 16 of life. No patient with a functioning shunt had postnatal pulmonary problems, whereas 3 without successful intervention had mild respiratory compromise. Conclusions: No definite advantage was noted in the small number of fetuses that underwent successful shunting. Successful shunt placement did not prevent renal insufficiency. The relief of oligohydraminos may benefit pulmonary function in some patients. The high technical failure and complication rates of in utero intervention should be considered before proceeding.