The purpose of this study was to evaluate the impact of routine hospitalization for fetal monitoring on the perinatal survival and neonatal morbidity of monoamniotic twins. This was a multicenter retrospective cohort analysis of 96 monoamniotic twin gestations from 11 university and private perinatal practices. Overall mortality rates were calculated. The risk of intrauterine fetal death and neonatal morbidity was compared among women who were observed as inpatients versus outpatients. The overall mortality rate from enrollment was 19.8% (mean gestational age at enrollment, 17.4 weeks). The perinatal mortality and corrected perinatal mortality rates were 15.4% and 12.6% , respectively. Eighty- seven women had both twins who were surviving at 24 weeks of gestation; 43 women were admitted electively for inpatient surveillance at a median gestational age of 26.5 weeks; the remainder of the women were followed as outpatients and admitted only for routine obstetric indications (median gestational age, 30.1 weeks). No intrauterine fetal deaths occurred in any hospitalized patient. The risk of intrauterine fetal death in women who were followed as outpatients was 14.8% (13/88) versus 0 for women who were followed as inpatients (P <. 001). There also were statistically significant improvements in birth weight, gestational age at delivery, and neonatal morbidity for women who were followed as inpatients. We observed improved neonatal survival and decreased perinatal morbidity among women who were admitted electively for inpatient fetal monitoring. The purpose of this study was to evaluate the impact of routine hospitalization for fetal monitoring on the perinatal survival and neonatal morbidity of monoamniotic twins. This was a multicenter retrospective cohort analysis of 96 monoamniotic twin gestations from 11 university and private perinatal practices. Overall mortality rates were calculated. The risk of intrauterine fetal death and neonatal morbidity was among among women who were observed as inpatients versus outpatients. The overall mortality rate from enrollment was 19.8% (mean gestational age at enrollment, 17.4 weeks). The perinatal mortality and corrected perinatal mortality rates were 15.4% and 12.6%, respectively. Eighty- seven women had both twins who were surviving at 24 weeks of gestation; 43 women were admitted electively for inpatient surveillance at a median gestational age of 26.5 weeks; the remainder of the women were followed as outpatients and admit only for routine obstetric indications (median gesta tional age, 30.1 weeks). No risk of intrauterine fetal death in women who were as outpatients was 14.8% (13/88) versus 0 for women who were followed as inpatients (P < . 001). There were were significant significant improvements in birth weight, gestational age at delivery, and neonatal morbidity for women who were followed as in patients.