The aim of the study was to evaluate leakage of liquid past the low-pressure cuffs of tracheal tubes. Ten samples of each of nine different types of tubes were tested in a PVC mock trachea, using intracuff pressures of 20, 30, 40 and 50 cmH2O. In five types of tubes, 6-10 cuffs allowed profuse leakage (> 20 ml water in 5 min) even at the highest intracuff pressure, i.e. 50 cmH2O. In the most efficient tube, all the cuffs were leak-proof (leakage < 5 ml in 5 min) at 40 cmH2O and in the second best type the cuffs were leak-proof at 50 cmH2O. The leakage of fluid past the tracheal tube remains an unresolved problem with low-pressure cuffs.