McDonald v. Board of Election Commissioners of Chicago, 394 U.S. 802 (1969),[1] was a unanimous decision by the Supreme Court of the United States that an Illinois law that denied absentee ballots to inmates awaiting trial did not violate their constitutional rights under the Fourteenth Amendment.

[2] The plaintiffs in this case, Sam L. McDonald and Andrew Byrd, were inmates awaiting trial in Cook County, Illinois.

McDonald and Byrd sued in federal court in Chicago,[3] arguing that their right to vote under the Equal Protection clause of the Fourteenth Amendment had been violated.

Writing for the majority, Chief Justice Warren first observed that the plaintiffs had two basic challenges to how Illinois had classified voters: first, that the distinction between medical incapacitated persons and the "judicially" incapacitated "bears no reasonable relationship to any legitimate state objective"; and second, that neither was there any good reason to distinguish between those in pretrial detention in their home county, and those detained elsewhere.

[1] Before dealing with these, the Court addressed the implicit argument that, because the right to vote was involved, some level of strict scrutiny was required: Such an exacting approach is not necessary here, however, for two readily apparent reasons.

Secondly, there is nothing in the record to indicate that the Illinois statutory scheme has an impact on appellants' ability to exercise the fundamental right to vote.