During cardiopulmonary resuscitation, when an intravenous line is not present or easily obtainable, the intracardiac injection of drugs has been a traditional route of choice. However, the intracardiac administration may be associated with serious complications. We have given epinephrine endotracheally to ten newborn infants who all had bradycardia that did not respond to ventilation with 100% oxygen, to heart compression or to bicarbonate infusion. Epinephrine, 0.1 mg/ml was injected directly into the tracheal tube, and ventilation was immediately continued. A standardized procedure has been chosen by giving 0.25 ml to the infants weighing less than 1 500 g, 0.5 ml to those weighing between 1 500 and 2 500 g, and 1.0 ml to those greater than 2 500 g. All infants had a return to normal heart rhythm within seconds after installation of the epinephrine solution. The establishment of an intravenous line in small infants can be difficult, and the infants are usually intubated before the injection of epinephrine is considered. The endotracheal route should therefore be the first route of choice in the absence of a rapidly obtainable vascular access.