The aim of this study is to understand the relationship among physical fitness, leisure-time activity levels, measures of body composition, and assessments of emotion toward physical activity in individuals with Down syndrome (DS). This is important because it could help individuals understand the importance of physical activity in this population. The BMI, waist circumference, height, weight, body fat percentage, and non-exercise estimation of aerobic capacity along with the temporary state of emotion toward physical activity of thirty participants with DS were measured. The results of our study show that individuals with DS who are more physically fit have less body fat and a lower BMI. They also took part in more leisure-time activity and expressed more effort during physical activity.