Cooper's old 7 p.m. EST show will be filled by an expanded version of "The Situation Room" with Wolf Blitzer, the late afternoon program attracting attention for its arresting use of multiple video screens.
With Brown left without a time slot, "we mutually looked at the lay of the land and came to this conclusion" that he would leave, said CNN/U.S. President Jon Klein.
Brown was vacationing this week, according to the network. A telephone call to his agent seeking comment was not immediately returned.
Klein said the switch was done to build CNN's schedule around what he considers its hottest personality, Cooper, and hottest new show, "The Situation Room."
Cooper, 38, has been gathering momentum all year that peaked with his on-the-scene coverage of Hurricane Katrina, Klein said.