Physical inactivity is a global public health problem, and it has been linked to many of the most serious illnesses facing many industrialized nations. There is little evidence examining the physical activity profile and determinants for the vulnerable population such as people with intellectual disabilities (ID). The present paper aims to describe the regular physical activity prevalence and to examine its determinants among adolescents with intellectual disabilities in Taiwan. Participants were recruited from 3 special education schools in Taiwan, with the entire response participants composed of 351 primary caregivers of adolescents with ID (age 16-18 years). There were 29.9% ID individuals had regular physical activity habits, and the main physical activities were walking, sports, and jogging. There were only 8% individuals with ID met the national physical activity recommendation in Taiwan which suggests at least exercise 3 times per week and 30 min per time. In a stepwise logistic regression analysis of regular physical activity habit, we found that the factors of caregiver's educational level and preference toward physical activity were variables that can significantly predict ID individuals who had regular physical activity habit in their daily livings after controlling other factors. To maximize the positive effect of physical activity on people with ID, the present study suggests that it is needed to initiate appropriate techniques used for motivation to participate in physical activity for this population. (Contains 6 tables.)