Prompt detection of oesophageal intubation is a primary concern in anaesthetic practice. This blind, randomised study evaluates three widely used tests of intubation. Forty patients had both their trachea and oesophagus intubated, each patient was studied twice. Auscultation of the epigastrium, right and left axilla is more reliable than auscultation of the chest, and the anaesthetist's feeling when he squeezes the bag. P = 0.001 and P = 0.048, respectively. The tests were carried out after gastric distension with gas had occurred. We conclude that auscultation of epigastrium, right and left axilla, are recommended.