Placement of nasogastric tubes is one of the most commonly performed diagnostic and therapeutic medical procedures. Proper placement of the tube in the digestive tract below the diaphragm is crucial for efficacy and safety. This study evaluates a magnet detection system that allows percutaneous non-radiographic localization of the nasogastric tube tip. Each volunteer subject had the magnet detector placed over the abdomen, and was then intubated with a magnet-tagged nasogastric tube. Eighty-eight nasogastric tube placements were performed in 22 volunteers. The detection system located the nasogastric tube tip below the diaphragm in all 88 placements. Location in all attempts was confirmed by fluoroscopy. This method of correctly locating the tip of nasogastric tubes may obviate the need for radiographic imaging in most cases.