Parents are asking a federal judge to force the Douglas County school district to let them use public vouchers to send their children to religious schools.
Thursday's court hearing in Denver is the latest in a long running legal battle over the vouchers.
The district originally allowed the vouchers to be used for religious schools but last year the Colorado Supreme Court that violated the state constitution.
The school district is appealing to the U.S. Supreme Court but, in the meantime, it has dropped religious schools from the program.