Increased life expectancy in persons with Down syndrome (DS) is associated with premature age-related changes. The aim of this study was to assess auditory function in adults with DS and to evaluate the prevalence of hearing loss in this population. Audiometric tests were performed in 72 adults with DS (mean age 37.3 ± 10.1 years, 51.4% females). Air conduction pure tone average (PTA) thresholds at frequencies 0.5-1-2-4 kHz were calculated to assess hearing function. Hearing loss was present if the PTA threshold was > 20 dB hearing level. Higher frequencies of 4 and 8 kHz were also assessed. Hearing loss was shown in 47 (65.3%) participants. The prevalence of hearing loss increased with age, ranging from 42.86% in the 20-29 years group to 90.91% in the 50-59 years group. High frequencies (4 and 8 kHz) were more often impaired than other frequencies used to measure PTA. Thus, the study concluded hearing loss is common in adults with DS and shows a pattern compatible with precocious aging of the hearing system. Auditory evaluation is strongly recommended in adults with DS.