This interdisciplinary long-term study examined the effects of recreational noise exposure on the hearing of adolescents. Boys and girls (aged 14-17 years) were examined during a four-year period. Audiological, psychosocial, and sound measurements were performed yearly to determine the hearing threshold level (HTL) of participants in the 250-16000 Hz range, their participation in recreational activities, and the sound levels at discos and through personal music player use. A tendency of the mean HTL to increase in both genders during the study was observed, especially at 14000 Hz and 16000 Hz. Boys had a higher mean HTL than girls. The participation in musical activities increased yearly, 'attendance at discos' being the favourite musical activity for both groups. In general, boys were more exposed to high sound levels than girls. The equivalent sound levels in discos ranged between 104.3 and 112.4 dBA, and between 75 and 105 dBA from personal music players.