A bed base comprises a rectangular support having side members connected at corners by a corner connector assembly including a locator element in a leg of a plate member that interacts with a locator element in a side member. A cross-rail assembly includes an elongated bar member that fits in notches in upper edge sections of opposed side members and a pair of leg members near opposed ends the elongated bar member pass through the notches upon attaching the cross-rail assembly to the rectangular support.