A major problem in the care of premature and other newborn infants is obtaining and maintaining correct position of an endotracheal tube. Improper placement of the distal tip of the endotracheal tube above the larynx or below the carina is a life-threatening hazard that not only impairs ventilation, but also may result in serious pulmonary complications such as lobar atelectasis and air leak. This problem was addressed by testing the hypothesis that a light source at the end of the endotracheal tube could be seen on the neck and chest and that, therefore, the endotracheal tube could be positioned and repositioned without radiologic guidance. The validity of this concept was confirmed in animals using a rigid bronchoscope light source and conventional endotracheal tubes. Then an endotracheal tube in which a fiberoptic strand was incorporated in the wall and which terminated near the tip of the tube was used. The illuminated endotracheal tube was used 33 times in 25 infants. This technique has been shown to provide a safe method (not requiring ionizing radiation) for positioning of the endotracheal tube by virtue of external visualization of a circle of light on the surface of the baby. This system will not permit differentiation of tracheal from esophageal intubation.