Aims: To assess the impact of oral conditions among children/adolescents with Down syndrome (DS) on the Oral Health-related Quality of Life (OHRQoL) of their families in comparison with a group without DS. Methods and Results: Families of 144 children/adolescents with DS aged 4-18 years were compared with families of individuals without DS. Dental caries experience (DMFT/dmft), clinical consequences of untreated dental caries (PUFA/pufa), gingival bleeding (GBI), visible plaque (VPI), and malocclusion were evaluated.