Caregiving is a complex health care activity, from an informal family level activity; it is becoming a major part of health care. In India, family members are mostly caregivers for persons with mental disabilities. The present study assessed the stress among the caregivers of mentally disabled children (Autistic Spectrum Disorder, Intellectual Disability, and Attention Deficit Hyperactivity Disorder) and found the association between stress and selected socio-demographic variables. This was an institutional based cross-sectional study with a duration of six months, i.e. from January 2019 to June 2019. This study was conducted among the caregivers availing services (therapies and follow-ups) at the National Institute for Empowerment of Persons with Multiple Disabilities, Chennai, Tamil Nadu. The level of stress was assessed using the Kingston Caregiver Stress Scale. This study was conducted with time-bound complete enumeration method, by which data from 101 participants were collected. The results of this study showed that 64.3% of the caregivers had the severe level of stress, 21.7% of the caregivers had a moderate level of stress and 13.8% of the caregivers had mild stress. Hence, it can be concluded that caregiver's stress is an important element to determine the burden and the unexplained psychological pressure a caregiver holds onto.