PURPOSE: to check the effect of acclimatization on sentence recognition in quiet environment and under noise, in new users of hearing aids, evaluated without their use, before and after the acclimatization period. METHODS: the study comprised 40 individuals, aged between 28 and 78year old with mild to moderate sensorineural hearing loss. They were starting the selection and adaptation process of hearing aids. The tests were conducted in three sessions, before the adaptation of hearing aids, fourteen days and three months later, respectively. they were applied to Portuguese Sentences Lists test (COSTA, 1997), in free field, in quiet environment and under noise, both in fixed 65 dB A intensity, in which we obtained the percentual indexes of sentences recognition in quiet environment (PISRQ) and under noise (PISRN). RESULTS: the mean values for PISRQ in the 1st, 2nd and 3rd sessions were, respectively, 65%; 72% e 83% dB A. The mean values of PISRN for the 1st, 2nd and 3rd sessions were 51%; 58% e 59% dB A, respectively. While comparing the results between sessions, there was a statistically significant difference for PISRQ between the 1st and 3rd e and between the 2nd and 3rd session, and for PISRN, between the 1st and 2nd e and between the 1st and 3rd session. CONCLUSION: the subjects improved their performance using hearing aids, even being evaluated without them, and this improvement may be related to the acclimatization effect.