The purpose of this study was to examine if neonatal mortality rates (NMR) based on birth weight discordance (BWD) differ based on mode of delivery. The population- based US “ matched multiple birth“ database (1995 to 1998) was used to examine the effect of vaginal/vaginal (VV) and cesarean/cesarean (CC)- modes of delivery (MOD) on neonatal mortality (< 28 days after birth). Births at < 32 weeks, congenital malformations, chromosomal anomalies, and discordant MOD (vaginal/cesar- ean) were excluded. The association between MOD (with CC as the reference) and neonatal mortality was expressed as relative risks (RR) with 95% CI, derived from logistic regression models. The NMR increased with increasing degrees of BWD regardless of mode of delivery. CC was associated with decreased NMR when BWD was between 20% and 40% , but this reached significance at BWD ≥ 40% ; VV pairs had a 1.6- fold (95% CI 1.1- 2.2) increased NMR compared with CC. In twins with BWD < 40% , MOD has no effect on NMR. Beyond or equal to 40% discordance, there was lower NMR with cesar- ean- cesarean delivery. The purpose of this study was to examine if neonatal mortality rates (NMR) based on birth weight discordance (BWD) differ based on mode of delivery. The population-based US ”matched multiple birth " database (1995 to 1998) was used to Births at <32 weeks, congenital malformations, chromosomal anomalies, and discordant MOD (MOD): neonatal mortality (<28 days after birth) The association between MOD (with CC as the reference) and neonatal mortality was expressed as relative risks (RR) with 95% CI, derived from logistic regression models. The NMR increased with increasing degrees of BWD regardless of mode of delivery. CC was associated with decreased NMR when BWD was between 20% and 40%, but this reached significance at BWD ≥ 40%; VV pairs had a 1.6- fold (95% CI 1.1-2.2); compared with CC. In twins with BWD <40%, MOD has no effect on NM R. Beyond or equal to 40% discordance, there was lower NMR with cesar-ean-cesarean delivery.