In June of 2006, Uwe Boll publicly announced a challenge to his numerous critics to "put up or shut up." Based on certain criteria, Boll will select five of his harshest critics to fight in a series of multi-round boxing matches to be held in Vancouver, British Columbia that will be broadcast over the Internet. He planned to use footage from these fights in this movie, but it was soon discovered that they don't fit into the plot of the movie, so the idea was dropped. It’s claimed that they might be part of the DVD when it’s released.
Gary Coleman was offered the chance to reprise his role as one of the central characters from the original Postal 2 (2002) (VG) video game, but turned down the offer because he didn't want to swear.
Uwe Boll only shot 3 to 5 takes of every scene in the movie. He thought that the biggest strength in comedy is the emotion behind the acting, which cannot be kept when trying the scenes too often.
Zack Ward originally auditioned for the role "Officer Greg". But the producers of the movie thought he would fit better into the role of the Postal Dude, so he got that part. The role for Officer Greg went to Chris Spencer instead.
This is the first movie in over 10 years that Uwe Boll actually wrote the script for.
As stated by Uwe Boll on several occasions and in the audio commentary on the DVD, no big agencies wanted their stars in the movie.
Lindsay Hollister was intended to play "Bitch", the Postal Dude's obese wife. But when producers found out that there is another movie (Good Luck Chuck (2007)) being filmed in Vancouver at the time and visited a day of shooting, they saw Jodie Stewart who "fit much better into the role because of her weight", so she was approached for the role moving Lindsay Hollister to a minor role.
As stated on the audio commentary on the German DVD, the movie was intended to be more satirical and more ridiculous ("Like Blues Brothers meets Borat") than the version that has been made. Executive Producers Steve Wik and Vince Desiderio, who lead Running With Scissors, didn't like the approach to the extent Uwe Boll wrote it, so he had to rewrite it together with Bryan C. Knight.
The script for the movie was first written in German only.
The Seminar Scene with Michael Robinson is stated to be completely improvised with 3 or 4 alternate speeches. Each of them are stated to go on for about 10 minutes and will probably be released on the Director's Cut DVD.
Release in the US was very hard. First it was planned for "Spring 2007" as mentioned in the first trailers which stated "This Spring" and was first shown in January 2007. Then it was stated to come out in June 2007, but was again hold back to September 2007. Finally it should have come out in "Spring 2008", so that new trailers wouldn't have to be made. But that was dropped again for a release on 23rd May, one day later as Indiana Jones and the Kingdom of the Crystal Skull (2008), claiming that Postal will "destroy Indiana Jones at the box office".
The scene with Osama bin Laden trying to get change back from the payphone was improvised. Larry Thomas came up with the idea when seeing the payphone and told Uwe Boll about it, who loved the idea. In the original script Osama was to call George W. Bush with his cellphone.
Abdul, the retarded taliban, is played by the owner of a local nightclub, according to Uwe Boll.