Sylvester Stallone trained for six months to get in shape for his role.
The bout between Rocky and Dixon was filmed with actors Sylvester Stallone and Antonio Tarver really hitting one another. According to Stallone, not a single punch in the fight was pulled, and every hit on film was a hit for real. Furthermore, Stallone has revealed that the scene where Rocky is knocked down for a 9 count, and is trying to get to his feet by taking hold of the rope, but is having difficulty focusing on it, is completely genuine; Tarver really did knock him down, and he really couldn't get up.
According to Sylvester Stallone, the shot of Rocky standing alone on the museum steps before the second set of end credits was actually filmed without him even knowing.
This is the only movie in the Rocky series not to begin with Rocky in a boxing match.
According to her gravestone, Adrian Balboa's death was on 11 January 2002.
The only Rocky movie where the famous red, white, and blue boxing trunks aren't being worn, even though the trunks are briefly shown through the use of archive footage. In Rocky II, they are only seen in the opening scene, which was the fight from the previous film.
Sylvester Stallone originally wanted to finish up Rambo (2008) before he could finish up Rocky Balboa (2006). However, Metro-Goldwyn-Mayer (MGM) gave him the green-light and Stallone had to put Rambo on hold.
In 2005, Sylvester Stallone published a men's fitness magazine called Sly. Although the magazine only lasted 4 issues, Stallone included portions of his script for this movie, including illustrations of some scenes. The drawing of Mason Dixon does not resemble Antonio Tarver, as the part had not yet been cast.
All of the arena material was filmed in HD to match the HBO PPV look; the rest of the film was shot on standard 35mm.
Although it is not included as a deleted scene on the DVD, Sylvester Stallone has said that a scene was filmed in which Rocky sees a woman that looks like Adrian in the building where Robert Jr. works. He follows her for a while before he realizes it is not Adrian. Stallone decided to cut the scene because he felt that Rocky's loneliness had already been established enough, and that this scene was overkill.
The computer simulation fight was based on The Super Fight (1970) which pitted Muhammad Ali against Rocky Marciano. Every possible scenario was considered and filmed and the computer decided that Marciano would win in the 13th round. When told of the result, Ali retorted "that computer was made in Alabama".
Andy (Don Sherman), the bartender from Rocky (1976), Rocky III (1982) and Rocky V (1990) can briefly be seen in this film sitting in a wheelchair in the background of his bar cheering on Rocky during the fight. Andy originally had a more sizable role, but the scene was cut from the finished film.
In the scene in the meat factory between Paulie and Rocky, Paulie asks if Rocky is angry because they took down his statue, a possible reference to the real life controversy which surrounded the statue. During the making of Rocky III (1982), a 9ft tall, 1500-pound bronze statue designed by A. Thomas Schomberg was placed at the top of the steps of the Philadelphia Museum of Arts. After filming wrapped, Sylvester Stallone tried to donate the statue to the museum but they said they didn't want it, sparking a huge debate between the Museum and the City's Art Commission about what constituted 'art'. The museum claimed the statue was nothing more than a "movie prop", and didn't want it. Local people were outraged, and the statue was ultimately placed in front of the Wachovia Spectrum in South Philadelphia. It was later returned to the Art Museum for the filming of Rocky V (1990), after which it was again moved to the front of the Spectrum.
"Take You Back", the song which opens the film, was first performed by Frank Stallone on a street corner in the original Rocky.
No traditional soundtrack was released for the film. Instead, a CD called "Rocky Balboa - The Best of Rocky" was released, featuring a collection of the best songs from the entire franchise. The release date of that compilation album (26 December, 2006) also coincided with the 30th anniversary re-release of the original soundtrack to Rocky (1976).