Developmental Disabilities Institute (DDI) is a non-profit organization that serves over 1,500 children and adults, providing educational, residential and vocational opportunities. Since 1961, the institute has been helping children with special needs, autism and other developmental disabilities. There are five total campuses located in Smithtown, Huntington, Medford, Riverhead and Ronkonkoma and 30 residential and day rehabilitation sites. The institute additionally provides family support services and sponsors a medical and dental clinic.