A rectangular paper or plastic film sheet has a pressure sensitive backing for sticking onto the curved top and sides of a regulation mailbox. The front face is imprinted with decorative graphics arranged to be seen from both sides. Below each graphic is imprinted an elongate address bar for receiving stick-on letters and numbers supplied in a color contrasting with the address bar for enhanced visibility. Partially cut through portions of the cover may be torn away to admit the indicating flag. The system is adapted for application without tools or special skills and enough letters and numbers are provided for identification of the mailbox as recommended by postal authorities.