The release date for the film was set before Spider-Man 2 was even released.

John Dykstra, who won an Oscar for his work as visual effects supervisor on Spider-Man 2, had declined to work on the third film. Instead, Dykstra chose to work on Hot Wheels. Scott Stokdyk took over as visual effects supervisor.

Topher Grace left "That '70s Show" to star in this movie.

The over 600 latex "web" balloons in the celebration scene had to be hand-painted with a Sharpie marker.

At the San Diego Comic-Con, on 22 July 2006, director Sam Raimi admitted that to keep the inclusion of the Venom character in this film secret, during casting and pre-production he went so far as to claim he hated the character, and had no intention of including the character in this film, or any subsequent sequels. To make amends, he then treated the audience to the first public images of Venom in the film, albeit with unfinished special effects.

Both Topher Grace and Thomas Haden Church confessed that when they were unceremoniously invited to meetings at Sony, they had no idea they would be auditioning for this film.

Originally, director Sam Raimi vehemently opposed having Venom as a villain in the film, claiming he hated Venom's "lack of humanity," but Marvel producer Avi Arad convinced him to include the character, explaining that Venom had a strong worldwide following. Raimi eventually came to appreciate the character, based on writer Alvin Sargent's script and actor Topher Grace's performance.

This film is reportedly the most expensive film ever made in U.S. dollars, with a budget of $250 million. This breaks King Kong’s record of $207 million, and in terms of adjusted dollars, would be third to Voyna i mir’s budget of $560 million.

Composer Danny Elfman does not return to provide the musical score for this film, citing creative differences with director Sam Raimi over the previous film. Instead, Christopher Young composes the film's score. Interestingly, Elfman turned down this film for Charlotte's Web, which is about a spider who uses her talents to do good.

Thomas Haden Church worked out for 16 months to build up his physique to portray Sandman.

In a fight scene where Spider-Man punches through Sandman's chest, congenital amputee boxer Baxter Humby took Tobey Maguire’s place in filming the scene. Humby, who was born without his right hand, helped deliver the intended effect of punching through Sandman's chest.

The film's visual effects designer, Scott Stokdyk, created a miniature of a skyscraper section at 1/16th scale, instead of using CGI, to save time and costs, and so that damage done to the building could be portrayed realistically.

The film's translation in Russia is "Spider-Man 3: Enemy in the Reflection"

According to Grant Curtis, in early production Vulture was originally going to be in the movie, but was later replaced by Venom.

Kirsten Dunst dyed her natural blond hair red for the role of Mary Jane Watson. Bryce Dallas Howard dyed her natural red hair blond for the role of Gwen Stacy.

Real sand was used in the scenes with Sandman, except where there were characters being buried/covered in sand. Real sand being possibly hazardous for such scenes, ground up corncobs were used as a substitute. It provided marvelous snacks for the cast and crew afterwards...

Partial scenes, where Spider-Man is hanging from the back of an armored car, where filmed in downtown Cleveland Ohio, due to expensive shooting prices in New York City.

Sam Raimi and Tobey Maguire were the driving forces that got Sandman into this film. During press interviews for the first two Spider-Man films, Raimi and Maguire repeatedly mentioned Sandman as a villain they would like to see in a future sequel.

Release prints were delivered in three parts, each with a fake title. Reels 1, 3, 5, "Timing Friend". Reels 4 and 5, "Back for More". Reels 5 and 7, "Listening Heart".

Spiderman 3 combines all three Raimi brothers. Sam Raimi as the director, Ivan Raimi as one of the writers and Ted Raimi as an actor in the role of Hoffman.

While being in the Venom costume, Topher Grace didn't drink any water during his breaks.