Objective: To describe genetic aspects and characteristics associated with premature aging in adults with Down syndrome. Method: A cross-sectional study was carried out of 28 individuals with Down syndrome, aged between 20 and 54 years old (13 women and 15 men), in a university community genetics program, who were referred by philanthropic institutions which offers support to people with disabilities and their families. The genetic and functional data were recorded in anamnesis forms. Results: Karyotype analysis revealed free trisomy 21, with only one hereditary case of translocation between chromosomes 15/21. In the sample group, functional difficulties were observed in locomotion, sedentary lifestyles, behavior disorders, memory loss and depression symptoms, as well as loss of autonomy at more advanced ages. Only three people had reading and writing skills and 16 had good social relationships and friend-making skills. Conclusion: The study confirms that premature aging in Down syndrome starts in adulthood, and therapeutic follow-up is recommended with the implementation of interventions to prevent deficits and stimulate cognition, and activities for quality of life.