Introduction: Anthropometry is a tool used to quantify the quantity and proportions of body tissue compartments, allowing nutritional evaluation and follow-up of diverse populations. Objective: To compare body adiposity in young Chileans with and without Down syndrome (DS) using anthropometric techniques. Methods: A comparative cross-sectional study was designed in 66 Chilean young people with and without DS. The group of young people with DS consisted of 16 males and 14 females, the control group GC (young people without DS) consisted of 18 males and 18 females. The age range ranged from 18 to 23 years. The data were grouped into three age ranges (18-19, 20-21 and 22-23 years). Weight, height, neck circumference and waist circumference were assessed. Body mass index (BMI) and waist-to-height ratio (WHR) were calculated. Results: Young people with DS reflected greater neck circumference (~3.6 to 4.3cm), waist (~4.1 to 11.7cm) and BMI (~0.03 to 0.05) in all age ranges relative to the CG (p<0.05). There were no significant differences in BMI (p>0.05). Young women with DS had higher values in neck circumference (~3.0 to 5.8cm), waist (~11.4 to 15.1cm), BMI (~5.6 to 7.5cm) and ECI (~0.10 to 0.11) compared to CG (p<0.05). Conclusion: The results have shown that youth with DS have elevated levels of body adiposity relative to their non-DS counterparts. These findings suggest the need to implement and encourage healthy lifestyle programs to maintain acceptable levels of body adiposity among youth.