Persistent fetal lower urinary tract obstruction carries a very poor prognosis secondary to damaged renal capacity and oligohydramnios, with its related pulmonary hypoplasia. Several attempts in the past several years to divert urinary flow via an intrauterine shunt have generally been disappointing, primarily because of poor patient selection. In this study we report our experiences with aggressive decompression of megacystis in 11 patients, the value in selected cases of sequential evaluations of fetal urine biochemistry, and the success of intrauterine bladder shunting procedures in appropriately chosen patients. Our data suggest that a single fetal urine determination may be insufficient to declare irreversible damage. Following decompression, improvement in urine biochemistry or its lack may be more likely representative of ultimate outcome. Decompression by either needle aspiration or intrauterine shunting is warranted in carefully selected cases and can save fetuses that are otherwise very likely doomed.