[1] Incumbent Senator Everett M. Dirksen, a Republican, won reelection to a fourth term.

No seats switched parties, leaving the Illinois House delegation to continue to consist of 12 Democrats and 12 Republicans.

Robert A. Dwyer, an insurance executive from Winnetka ran unopposed for the Republican nomination.

Incumbent Clerk of the Supreme Court Fae Searcy died in office on March 25, 1968.

An election using cumulative voting was held for three of nine seats for Trustees of University of Illinois system.

[1][6] Incumbent Democrat Kenney E. Williamson (appointed in 1967 after the death in office of Wayne A. Johnston) lost reelection.

[1] In order to be approved, legislatively referred state statues required the support of a majority of those voting on the statute.

[1] A call for a constitutional convention required votes equal to a majority of the all ballots cast in the general election.

The chief sponsor of the legislation that created this ballot measure was Senate Republican leader W. Russell Arrington.

[11] The call for the convention required the votes of an equal majority of all ballots cast in the 1968 general elections.