Though the temporary rooms in this museum are the showiest, the most interesting exhibition is a permanent one that houses just over 200,000 pieces. The room has huge shelves that, when opened, reveal an amazing collection of postal stamps.

The collection includes items ranging from the coveted Penny Black (the first adhesive postage stamp in the world) to a vibrant collection of fluorescent stamps. There is also a shelf dedicated to stamps in times of war, one for commemorative historical stamps, and a map with prominent stamps from each country in the world.

The museum originally opened as a temporary stamp exhibition. But after collector Alfredo Harp Helú decided to donate his collection for a permanent exhibition, it opened as the Museo de la Filatelia Oaxaca.

When admiring the stamps, look closely at the details. An eagle eye will spot a postage stamp issued for a trip by Amelia Earhart, though it was considered speculative for not going on sale and because the ink had to be bought from the United States. The philatelists created a postage stamp as a parody that had a black cat and the legend "Emilia Sin Hearth" (Emilia without Heart).

The museum even houses the collection of baseball player Forrest "Spook" Jacobs, whose hobby was philately relative to baseball. The most amazing are seven stamps autographed by Babe Ruth. The collection also highlights the collection of David Braun, who was dedicated to collecting stamps related to bridges from around the world.

Other jewels in the exhibit are a series of letters that Frida Kahlo wrote to her doctor Leo Eloesser, which bare the artist's symptoms; the collection of stamps that have been issued since 1904 to combat Tuberculosis; and the collection that shows the first stamp issued in Mexico.

An outstanding section is the artistic zone that protects the correspondence of different artists who created works of art with stamps and postage stamps. Among the works are pieces by Toledo, Felipe Ehrenberg, Emy Winter, Michael Thompson, Jas Felter, and Clemente Padón.