Trivia

Colin Farrell was in talks to play Watson before Jude Law was cast.

The first Sherlock Holmes film to reach U.S. movie theaters in over twenty years, since the 1988 comedy Without a Clue (1988) with Michael Caine as Reginald Kincaid/"Sherlock Holmes".

Robert Maillet accidentally knocked out Robert Downey Jr. while filming a fight scene.

Robert Downey Jr. read many Sherlock Holmes stories and watched "The Adventures of Sherlock Holmes" (1984) by Granada Television (starring Jeremy Brett) in order to learn more about the character.

Sienna Miller was in talks for a role before her ex-fiancé Jude Law was cast as Watson.

The song that plays from 1:03 to the end on the second trailer is a piece called "Unstoppable" by the group E.S. Posthumus (specifically 1:47 to the end on the track).

The set for Sherlock Holmes's home in this film was previously used as Sirius Black's home in Harry Potter and the Order of the Phoenix (2007).

The part of Sherlock Holmes has been previously played by Michael Caine, while Watson is played in this film by Jude Law. Law took over Caine's role in Alfie (2004) and Sleuth (2007), appearing together with him in the latter film.

There were rumors that Brad Pitt has been cast as Moriarty and re shoots have taken place, but the rumors were quickly denied.

Guy Ritchie's first film not to be Rated R in the US.

Guy Ritchie's first film to be rated 12 in his native country U.K.

The outfits worn by the navvies are the same ones worn by the railway workers in "Cranford: Part One: August 1844 (#2.1)" (2009).

Delivered to some theaters under the fake title "Elementary Education".

Watson's line to Holmes, "You know that what you're drinking is for eye surgery," is an obscure reference to Holmes's cocaine usage. At the time, cocaine was used as a topical anesthetic for eye surgery. In the stories, Holmes injects cocaine.

The first scene in Baker Street is a nod to Granada Television's "The Adventures of Sherlock Holmes" (1984) series, starring Jeremy Brett. In the scene, the camera focuses on a "Baker Street" street sign, then tracks backward down the street and over a clopping horse pulling a carriage. This same camera shot and angle - with the overhead tracking shot over a horse and carriage - was used to reveal Baker Street in the opening credits sequence of the Granada TV series.

At the end of the film, Mary asks Watson if she could read his journals of his adventures with Sherlock Holmes. Of the 60 Doyle penned stories of Sherlock Holmes, all but four have Watson serving as the narrator.

Although Irene Adler plays a large role in the movie, she only appears in one Sir Arthur Conan Doyle story, A Scandal in Bohemia, briefly referenced in the movie.

The story His Last Bow mentions that Holmes practiced shooting his pistol by putting VR (Victoria Regina) on his wall with bullet holes. In the movie, Holmes shoots VR in the wall in his room with a gun.

The four symbols referred to in the movie, the Man, the Lion, the Ox and the Eagle, are also attributed to the four Gospels of the Christian Bible: Matthew (the Lion, kingship), Mark (the Ox, servitude), Luke (Man, the humanity of Christ), and John ( Eagle, the divinity of Christ).

Rachel McAdams, Jude Law and Robert Downey Jr. reportedly did most of their own stunts.