Intraosseous administration of resuscitation medications and fluids in preterm and term neonates is an alternative when intravascular access is not possible with intravenous catheters or needles. Intraosseous access is rarely needed in neonates because of the availability of clinicians with expert technical skills for placement of intravenous catheters in neonatal ICUs, the presence of the umbilical vein during the first days after birth when most resuscitations occur, and the predominance of resuscitations being responsive to positive-pressure ventilation alone. Intraosseous access is most likely to be needed in out-of-hospital settings and in hospitalized infants without intravenous access who have vascular collapse secondary to shock or when clinicians responsible for vascular access during resuscitations are more skilled in intraosseous access than intravenous access.