IDEA first came into being on October 30, 1990 when the "Education of the Handicapped Act" was renamed "Individuals with Disabilities Education Act." (Pub. L. No. 101-476, 104 Stat. 1142). IDEA received minor amendments in October 1991 (Pub. L. No. 102-119, 105 Stat. 587).
IDEA received significant amendments in 1997. The definition of disabled children expanded to include developmentally delayed children between three and nine years of age. It also required parents to attempt to resolve disputes with schools and Local Educational Agencies (LEAs) through mediation, and provided a process for doing so. The amendments authorized additional grants for technology, disabled infants and toddlers, parent training, and professional development. (Pub. L. No. 105-17, 111 Stat. 37).
On December 3, 2004, IDEA was amended by the Individuals With Disabilities Education Improvement Act of 2004, though the abbreviation remains "IDEA." Several provisions aligned IDEA with the No Child Left Behind Act of 2001. It authorized fifteen states to implement 3-year IEPs on a trial basis. More concrete provisions relating to discipline of special education students was also added. (Pub. L. No. 108-446, 118 Stat. 2647)