Transient evoked otoacoustic emission (TEOAE) has proven to be a useful clinical screening test for auditory dysfunction. Problems concerning the evaluation are mainly due to irregularities of the physiological middle ear functions. In this study different degrees of middle ear alterations of otherwise normal-hearing children were quantified by means of tympanometry, otoscopy and pure-tone audiometry and then related to the results of TEOAE registration which were classified by the coefficient of the crosscorrelation and the frequency response spectrum. Data were obtained from 266 ears of 148 children between the age of 3 months and 11 years. The results indicate that even slight middle ear irregularities, e.g. negative pressure between -50 and -100 mm H2O, can reduce the rate of successfully recorded TEOAE from 95% (70/74) in the normal group to 78% (34/47). When children displayed a tympanogramm with no observable peak, a successful registration of TEOAE was possible in only 12% (n = 34) of the cases. Such results are related to serous or mucoid effusions which probably prevent a transmission of the emission from the cochlea to the meatus. In analysing the relation between conductive losses in pure-tone audiometry and TEOAE it was demonstrated that no TEOAE could be recorded in ears with a conductive loss above 20 dB HL. Where the conductive loss is smaller than 20 dB HL it is not possible to predict whether a reliable emission can be recorded or not. This study emphasizes the need to reexamine children who do not show positive emissions connected with middle ear imbalances.(ABSTRACT TRUNCATED AT 250 WORDS)