Abstract: A replacement mailbox post for mounting onto an old mailbox post. A four sided vertically extending replacement post has a hollow interior sized to mount to the old mailbox post. The internal cross-sectional area of the replacement post is geometrically compatible with the old post. A horizontally extending shelf has a proximal end extending into a pair of internal slots formed in the replacement post. A wall perpendicularly joined to the shelf extends downwardly therefrom at the proximal end covering an opening in the replacement post. Fastening devices extend through the replacement post into the wall. Additional fastening devices secure the replacement post to the old post. A decorative cover is mounted atop an encloses the hollow interior of the replacement post.