CHICAGO (AP) _ A federal judge has declared Illinois' Good Friday school holiday unconstitutional.

The state-mandated holiday for teachers and schoolchildren ''was primarily motivated by a desire to endorse the Christian faith and conveys the impermissible message that Christianity is a favored religion within the state of Illinois,'' U.S. District Judge Ann C. Williams said in a ruling released Tuesday.

''Unlike Christmas and Thanksgiving, which have both secular and religious connotations, Good Friday remains (a) wholly religious day.''

Williams barred the state from observing the school holiday, created by the Legislature in 1941. No other branch of state government is required to observe the holiday.

Andrea Metzl, who teaches students with learning disabilities in Chicago, had challenged the establishment of the school holiday. She said she does not observe Good Friday and could not explain the holiday to students without ''awkwardness and embarrassment.''

The ruling ''advances religious liberty for all Illinois schoolchildren,'' said Charlotte Newberger, president of the Midwest region of the American Jewish Congress, which supported Metzl's lawsuit.