Producer Andrew Macdonald read Irvine Welsh's novel on a plane in December 1993 and felt it could be adapted into a film, bringing it to director Danny Boyle and writer John Hodge in February 1994.

To convince Irvine Welsh to option the book, Danny Boyle wrote him a letter stating that Hodge and Macdonald were 'the two most important Scotsmen since Kenny Dalglish and Alex Ferguson'.

Welsh recalled that earlier suitors for the book's rights wanted to make a 'po-faced piece of social realism' like Christiane F or The Basketball Diaries, but was won over by the filmmakers' desire to reach a wide audience rather than just an arthouse one.

For the role of Renton, Boyle wanted a mix of Michael Caine's character in Alfie and Malcolm McDowell's Alex in A Clockwork Orange—someone repulsive yet charming; Ewan McGregor shaved his head and lost 2 stone (about 12.7 kg) for the part.

Ewen Bremner, who plays Spud, had actually played Renton in the original stage adaptation of Trainspotting.

Jonny Lee Miller impressed Boyle during his audition by performing a Sean Connery impression, after Boyle had heard about him playing an American in the film Hackers.

Boyle initially considered Christopher Eccleston for the role of Begbie due to his resemblance to the character as imagined in the novel, but ultimately cast Robert Carlyle, convincing the shorter actor by telling him 'small psychos are better.'

Kelly Macdonald, who made her film debut as Diane, was cast after the filmmakers sent flyers to nightclubs and boutiques and approached people on the street looking for an unknown actress who could convincingly play a character younger than her real age.

The casting of Keith Allen as the Dealer was a deliberate nod to his role in Boyle's previous film Shallow Grave, implying he plays the same character in both films.

The scene where Renton dives into the toilet is a reference to Thomas Pynchon's 1973 novel Gravity's Rainbow.

Ewan McGregor met with members of the Calton Athletic Recovery Group, an organisation of recovering heroin addicts in Glasgow, who also appear as the opposing football team in the opening credits; he was taught how to cook heroin using glucose powder and a spoon.

The film was shot in just seven weeks on a budget of £1.5 million, with cast and crew working out of an abandoned cigarette factory in Glasgow, and most scenes were done in a single take due to time and budget constraints.

Although the story is set in Edinburgh, almost the entire film was shot in Glasgow; only the opening chase scene was actually filmed in Edinburgh, on Princes Street and Calton Road.

For the scene where Renton sinks into the floor after overdosing, the crew built a platform above a trap door and lowered the actor down through it.

The infamous faeces in the 'Worst Toilet in Scotland' scene was actually made from chocolate.

Danny Boyle approached Oasis about contributing a song to the soundtrack, but Noel Gallagher turned down the opportunity because he mistakenly believed the film was about actual trainspotters.

U.S. Senator Bob Dole publicly accused the film of moral depravity and glorifying drug use during the 1996 presidential campaign, despite later admitting he had not actually seen it.

Trainspotting was screened out of competition at the 1996 Cannes Film Festival, reportedly because of its subject matter.