Introduction: Transient Evoked Otoacustic Emissions (TEOAE) is still recent in Brazil and there are few studies in this field. TEOAE during breast feeding is commonly performed. However, daily practice suggests that suction noises interfere with the test results. Objective: To verify whether or not the noises produced by suction interferes with the results of TEOAE test, when compared to TEOAE obtained during natural sleep. Methods: We studied 147 normal newborns without risk factors for deafness (284 ears), attended at the nursery of Hospital Santa Luzia in Brasília. They were tested during natural sleep and during breast feeding (with and without eclosions). Results: There were statistically significant differences between the results of the tests performed during natural sleep and breast feedings. There were no differences among gender when eclosion noises were present during suction. Conclusions: The results of TEOAE during breast feedings should be cautiously interpreted.