Background: The evidence on the effect of age on the receptive and expressive language skills of individuals with Down syndrome is inconclusive. Recent research highlights the relevance of having tools to detect age-related changes in language skills. Method: Data were collected on 45 adults with Down syndrome. All were assessed with the Peabody test, token test, verbal fluency tasks and an expressive language sample. Results: Scores on token and Peabody showed a decline in older adults, whereas no significant effect of age was observed for expressive language measures. A quadratic regression confirmed the association between age and receptive language measures. Highly significant associations were also found between the performance on receptive and expressive language measures. Conclusions: Receptive language skills are more age-sensitive than the expressive language skills. In addition to expressive language skills, receptive language skills should be measured because they show age associated changes not observed in expressive language.