Abstract: A rotatable mailbox mounting assembly which when permanently mounted on an existing round or square support post or extended arm, with a mailbox mounted thereupon, will allow the mailbox to be rotated 360 degrees in either direction. The mailbox is held in a firm mail receiving position by a ball detent mechanism. The mechanism consists of one spring and two balls opposite one another The spring forces the balls into two detent grooves, thus holding the mailbox firmly in a mail receiving position. When a predetermined force is exerted on the front or rear of the mailbox, the spring-loaded balls are forced out of their "home" or detent position, thus allowing the mailbox to be rotated so that the mail can be retrieved from the rear, thereby avoiding the need to walk onto a roadway to retrieve mail. The unit is compact, fitting neatly into the recess in the bottom of all commercially manufactured mailboxes. The materials used and design make it durable and low-maintenance.