The act excludes: "the insane and epileptics and persons who have been insane within five years previous; persons who have had two or more attacks of insanity at any time previously,” among other categories. "Insanity" is described “as a deranged condition, characterized by delusions, depression, or homicidal tendencies.”

Immigration continues to be tied to ableism and a person’s ability to work. Immigrants are also excluded based on their political ideology. Also known as the "Anarchist Exclusion Act," the act allows for the exclusion and deportation of people viewed as anarchists: "those who believe in or advocate the overthrow by force of violence of the Government of the United States or of all governments or of all forms of law, or the assassination of public officials."

The 1903 act also increases public health exclusions.