CONTEXT: Mirror Syndrome or Ballantyne's Syndrome is a rare scenario of water retention in a pregnant woman associated with fetal and placental hydrops. OBJECTIVE: Awareness of the syndrome is important due to the associated fetal and maternal risks. Rh isoimmunisation as a cause is potentially treatable. METHODS: Study Design: Case Report PATIENT: A 28-year-old woman, gravida 4, para 1+1+1+1, presented at 24weeks gestation with abdominal wall edema and pedal edema and 4 kg weight gain in one week. the blood pressure was 150/100mm Hg with proteinuria. Sonographic evaluation revealed fetal scalp edema, ascites, cardiomegaly and placentomegaly. She was found to be Rh isoimmunised with no history on anti-D prophylaxis in previous pregnancies. The first pregnancy was uneventful, second an abortion and third was a preterm IUD with hydrops in baby. Provisional diagnosis of Rh Isoimmunisation with Pre- Eclampsia was made. INTERVENTION(s) Patient was started on anti hypertensives and multiple emergency intra-uterine transfusions (IUT) were given. The hydrops resolved after fourth IUT. Fetal ascites was drained once. Thereafter the patient has undergone three further IUTs (last at 34 wks). MAIN OUTCOME MEASURES: Resolution of fetal hydrops, maternal edema, period of gestation at delivery, neonatal outcome. RESULTS: There was also a concomitant complete resolution of matenal edema, blood pressure was normal without anti hypertensives, proteinuria resolved confirming the diagnosis of mirror syndrome. She is planned for delivery at 36 wks. Neonatal outcome is awaited next week (expected to be good). CONCLUSION: The condition of mirror syndrome is frequently mistaken for preeclampsia, although distinguishing characteristics can be identified. Mirror syndrome is a manifestation of extremely severe fetal hydrops and when associated with Rh Isoimmunisaton is completely reversible reducing maternal and neonatal morbidity and mortality.