Among obstetricians and neonatologists in administrative roles in New York City hospitals, a survey was initiated to compare the physicians' definitions of live birth and fetal death, the gestational age at which they consider infants viable, and the resuscitation practices of the neonatologists. The target survey population was 34 neonatologists, and 39 obstetricians representing 41 of the City's 43 maternity hospitals. A telephone survey was used to gather qualitative data from the physicians regarding their definitions of live birth, fetal death, and viability, and their practices regarding extremely premature births. Surveys were completed for 58 physicians, a response rate of 79% (94% for neonatologists and 67% for obstetricians). Physicians' definitions of live birth and fetal death varied, with almost a third (29%) of physicians including gestational age as part of their live birth criteria. Most of the physicians (90%) consider infants born at ≥23 weeks gestation viable. Most neonatologists (97%) said they always resuscitate infants born at ≥23 weeks gestation, and most (94%) said they would never resuscitate infants born at <20 weeks gestation. For infants born at 20-22 weeks gestation, there were differences in resuscitation practices. There is a gap between clinical practices and reporting requirements for live birth and fetal death. Whereas reporting requirements are based on definitions of live birth and fetal death, physicians make resuscitation and other clinical decisions regarding extremely premature infants based on definitions of viability.