Photographer Adam Stanheight and oncologist Dr. Lawrence Gordon awaken in a dilapidated bathroom, chained by their ankles to pipes on the opposite sides of the room. Between them lies a corpse, holding a revolver and a microcassette recorder. Both men find a tape in their pockets, and Adam quickly retrieves the tape player. A distorted voice on his cassette urges him to escape. Gordon's recording, on the other hand, tells him to kill Adam by 6 o'clock, as otherwise, his wife, Alison, and his daughter, Diana will be executed. Adam then finds a bag containing two hacksaws inside a toilet tank. However, as they try to cut through their chains, Adam's saw breaks eventually. Thereby, Gordon realizes the saws aren't meant to cut through their chains but to cut off their feet, concluding that they were abducted by a wanted serial killer known as Jigsaw. As he tells Adam about the killer, who tests his victims' will to live by forcing them to fight for their lives in his deadly games, Gordon admits that he was a former suspect in the case.
Through flashbacks, the audience learns how the doctor got involved in the homicide investigation. Five months earlier, Gordon had introduced his medical students to John Kramer, a terminal cancer patient, when he was visited by Detective David Tapp and Detective Steven Sing. They had found his penlight at the scene of Jigsaw's latest game. Although Gordon's alibi cleared him, he agreed to listen to the testimony of Amanda Young, a heroin addict and the only known survivor of one of Jigsaw's games. Shortly after Gordon was allowed to leave the police station, Tapp and Sing discovered Jigsaw's hideout in an abandoned mannequin factory after finding a clue on a videotape used by the killer during Amanda's game. Upon their arrival, they found Jigsaw and took him by surprise, saving another victim named Jeff Ridenhour in the process. However, the killer suddenly slashed Tapp's throat with a hidden blade, allowing him to escape custody. When Sing pursued him, he accidentally triggered a booby trap and was killed by four shotguns.
In the present, Alison and Diana Gordon are held captive in their apartment as their captor watches Adam and Dr. Gordon via a hidden camera. At the same time, the house is observed by David Tapp, who suffered a mental breakdown after Sing's death and was subsequently discharged from the Metropolitan Police Department. However, because of his feelings of guilt, he decided to continue the investigation on his own to end Jigsaw's games for good. As he still considers Gordon the main suspect, Tapp rented a run-down flat across from the doctor's house to keep an eye on him.
Meanwhile, Gordon finds a hidden box in the bathroom, which contains two cigarettes, a lighter, and a one-way cellphone. As time passes by, he and Adam both remember how they were abducted by a mysterious figure with a pig mask the night before, when suddenly, the phone rings. As Gordon answers the call, Alison, held at gunpoint by her captor, warns her husband not to trust Adam, stating that the latter knew everything about him. When Gordon confronts his fellow prisoner with Alison's warning, Adam eventually admits that Tapp had hired him to spy on the doctor. Furthermore, he shows him the photos he took of him, which he found in the same bag as the hacksaws. Thereby, Adam reveals his knowledge of Gordon having an affair with one of his medical students, Carla, whom he had met at a hotel on the night of his abduction. However, he realizes that one of the photos, which shows Alison and Diana's captor standing at a window in Gordon's apartment, wasn't taken by him. Upon looking at it, Gordon identifies the man as Zep Hindle, an orderly from the hospital where he worked.
Seconds later, the clock strikes six, marking the end of their game. As Gordon hadn't managed to kill Adam in time, Zep prepares himself to execute Gordon's family and calls the doctor so Alison can inform him about his failure. However, Alison secretly freed herself from her restraints and engages in a fight with her captor. The struggle attracts Tapp's attention, who storms into the apartment and opens fire on Zep, thereby giving Alison and Diana the chance to escape. Zep flees the scene and sets out for the bathroom to kill Gordon. Tapp pursues him to an underground tunnel network where the bathroom is located and brutally batters his opponent, but is ultimately shot in the chest and succumbs to his wound.
Meanwhile, Gordon, who doesn't know about his family's survival, suffers a mental breakdown. In a last desperate attempt to save the two of them, he uses his hacksaw to cut off his foot. Then, he takes the gun from the lifeless body in the middle of the room and shoots Adam, who collapses immediately. Moments later, Zep enters the bathroom and prepares himself to shoot Gordon but is attacked by Adam, who survived the gunshot. After a brief fight, Adam gains the upper hand and bludgeons Zep to death with the toilet tank lid.
Gordon, albeit severely injured, promises to get help and crawls out of the room. Once he is alone, Adam searches Zep's body for a key to his shackle but only finds another audiotape. Upon playing the recording, he learns that Zep himself was just another victim of Jigsaw. The latter had injected him with a slow-acting poison and ordered him to capture and kill Gordon's family if the doctor failed his test. In return for that, Zep would've been given the antidote.
When the tape ends, the corpse in the middle of the room arises and is revealed to be John Kramer, the real Jigsaw Killer, who began his murder series after being diagnosed with an inoperable brain tumor. He tells Adam that the key to his chain is in the bathtub he woke up in. However, it went down the drain when Adam initially scrambled from the tub. Horrified by these events, Adam grabs Zep's gun and tries to shoot Kramer but is incapacitated by an electric shock. Deciding that Adam didn't learn his lesson, Kramer turns off the lights and closes the door, leaving the screaming young man to die.
- Leigh Whannell as Adam
- Cary Elwes as Dr. Lawrence Gordon
- Danny Glover as Detective David Tapp
- Ken Leung as Detective Steven Sing
- Dina Meyer as Kerry
- Mike Butters as Paul
- Paul Gutrecht as Mark
- Michael Emerson as Zep Hindle
- Benito Martinez as Brett
- Shawnee Smith as Amanda
- Makenzie Vega as Diana Gordon
- Monica Potter as Alison Gordon
- Ned Bellamy as Jeff
- Alexandra Chun as Carla
- Avner Garbi as Father
- Tobin Bell as Jigsaw
After finishing film school in Australia, James Wan and Leigh Whannell started to work on their script for Saw, planning to finance the film themselves. This decision resulted in the rather minimalistic idea of having only a small, rather contained set with as few actors as possible. However, during the development of the script, it became evident that they didn't have sufficient funds to shoot the film on their own.
The script was optioned by a producer in Sydney for a year, but the deal eventually fell through. Finally, after other failed attempts to get the script produced in Australia from 2001 to 2002, literary agent Ken Greenblat read the script and suggested traveling to Los Angeles. Wan and Whannell initially refused due to the lack of travel funds. However, their agent, Stacey Testro, convinced them to go as they had better chances of finding a studio interested in producing the film in LA. To rouse potential studios' interest in the script, Whannell provided A$5,000 to make a short film based on the scene of Amanda's interrogation, which they thought would prove most effective. Whannell played David, a hospital orderly tested in one of Jigsaw's games. Working at the Australian Broadcasting Corporation, Whannell and Wan had connections to camera operators who were willing to provide technical assistance for the short film. Wan shot the movie with a 16mm camera in over two days and transferred the footage to DVDs to ship along with the script. Whannell wanted to play the lead character in the feature film, while Wan intended to be the director.
Eventually, the short film, along with the script, attracted the attention of Oren Koules, Gregg Hoffman, and Mark Burg, who worked as producers for Twisted Pictures. As they were fascinated with the film's concept, they decided to produce it, with Whannell playing the leading role of Adam, while Wan directed the film. The film was granted a production budget between $1 million and $1.2 million. The principal photography started on September 22, 2003, at the Lacy Street Production Facility in Los Angeles and went on for 18 days. The bathroom was the only set that had to be built. Danny Glover completed his scenes within two days. Due to the tight shooting schedule, Wan could not afford to shoot more than a couple of takes per actor. In post-production, Wan found he did not have enough shots or takes to work with as he was basically shooting rehearsals. Having numerous missing gaps in the final product, he and editor Kevin Greutert created shots to mend together during editing, such as making a shot look like a surveillance camera feed and using still photographs.
Lions Gate Entertainment picked up worldwide distribution rights for Saw when the films were shown at the Sundance Film Festival, only days before the film premiered on January 19, 2004. It was the closing film at the Toronto International Film Festival on September 18, 2004. Lionsgate initially planned to release the movie direct-to-video, but due to the positive reaction at Sundance, they chose to release it theatrically on Halloween.
It was released on October 1, 2004, in the United Kingdom, on October 29, 2004, in the United States, and on December 2, 2004, in Australia. The film was initially rated NC-17 by the Motion Picture Association of America for the graphic depiction of violence, but it was released with an R-rating after being re-edited. In addition, Lionsgate held the first annual "Give Til It Hurts" blood drive for the Red Cross and collected 4,249 pints of blood.
On October 31, 2014, Saw was re-released in honor of its 10th anniversary. However, it earned only $650,051 in its opening weekend and therefore is the third lowest-grossing wide opening. At the end of its run, the release had grossed $815,324, bringing the film's overall domestic gross to $56,000,369.
The theatrical version of the film was released on VHS and DVD on February 15, 2005, in the United States. After its first week, it earned $9.4 million in DVD rentals and $1.7 million in VHS rentals, making it the top rental of the week. A two-disc "Uncut Edition" was released on October 18, 2005, to tie in with the release Saw II. Additionally, the short film, also titled Saw, was included on the DVD.
The film was subsequently included in a boxed set with all six sequels entitled Saw: The Complete Movie Collection, which was released in September 2014 to celebrate the film's 10th anniversary. The box contained the unrated editions of all seven films, though it lacked any of the special features from previous releases.
Saw was a financial success. Shot on a meager budget of about $1.2 million, it earned over $55 million at the box office in the U.S. alone and $102,917,772 worldwide.  Generally, the critical reactions to the film were mixed. It received a rating of 48% from Rotten Tomatoes, based on 181 reviews, while Metacritic gave it a score of 46 out of 100, based on 32 critics. Most of the criticism regarded the general plot and the ending, which were considered "convoluted."
The soundtrack was mainly composed by Charlie Clouser, which took six weeks to complete. Other songs were performed by Front Line Assembly, Fear Factory, Enemy, Pitbull Daycare, and Psycho Pumps. In addition, Megadeth's song "Die Dead Enough" was initially set to be featured in the film but was not used for undisclosed reasons. The soundtrack was released on October 5, 2004, by Koch Records.
1. Tape Deck
3. Hello, Mark
6. Drill & Trap
7. X Marks
9. Out of Time
10. Tapp & Zepp
13. The Rules
14. Be Alright
15. Hello Zepp
16. Zepp Overture
4. Tape Deck
5. Hello, Adam
6. Follow Heart
7. Last I Heard
8. Hello, Paul
9. Razor Cage
10. Hello, Mark
11. We'd Like
12. In Your Own Time
13. Reverse Beartrap
14. Then I Saw
15. You Are in Fact
16. I Can See You
17. Diana 1
21. Diana 2
22. I See You
23. Sewer Runs
26. Drill + Tapp
27. Sing + Get You
28. X Marks
29. Last Night
33. Bad Man
34. Who Are You?
35. Hotel Garage
36. Not a Cop
37. I Didn't Cheat
39. Out of Time (A)
40. Out of Time (B)
41. Tapp + Zepp
42. Car Chase
45. I've Done It
46. The Rules
47. Be Alright + Lie
48. Hello Zepp
49. Zepp Overture
1. Stürm – Front Line Assembly
2. Bite the Hand That Bleeds – Fear Factory
3. Action – Enemy
4. You Make Me Feel So Dead – Pitbull Daycare
5. Wonderful World – Psychopomps
- Originally, Adam and Lawrence were to be trapped on a lift or in a basement.
- Director James Wan created Billy the Puppet for the film.
- The film was shot within 18 days, with pre-production lasting only five days.
- Shawnee Smith, who played Amanda, filmed all of her scenes within a single day and was sick during the shooting.
- Producer Oren Koules has an uncredited cameo as Donnie Greco.
- All scenes set in the bathroom were filmed in chronological order within six days.
- While shooting the scene of Lawrence cutting off his foot, actor Cary Elwes accidentally scratched his foot despite the saw being blunt.
- Besides the role of Adam, Leigh Whannell also played Sing during reshoots when actor Ken Leung was unavailable. He plays Sing when he enters Jigsaw's hideout and when he gets shot later on. In addition, Whannell's hands were used as the stand-in for Shawnee Smith's hands during close-ups of Amanda sifting through Donnie Greco's intestines.
- Sing's chase after Jigsaw was the last scene to be filmed.
- Director James Wan did not get paid and instead got a percentage of the profits.
- When reviewing the locations of recent fire reports, Tapp and Sing used a map of Washington D.C.
- After Lawrence cut off his foot, in the scene where he tries to shoot at Zep with an empty revolver, Cary Elwes wore a black shaggy sock to cover his foot.
- While filming the scenes of Paul's death and the subsequent investigation of the crime scene, camera operator David Armstrong accidentally bumped against the ceiling and had to be taken to a hospital due to a mild concussion.