Sergio Leone originally wanted Lee Marvin for the role of Douglas Mortimer.

Aldo Sambrell's character name "Cochelio" is the English spelling of the Spanish word "cuchillo", which means knife.

Lee Van Cleef claimed to be faster on the draw than Clint Eastwood. He took three frames of film (one eighth of a second) to draw, cock and fire.

The safe that Indio robs with his gang in El Paso contains Confederate dollar notes.

The Man With No Name (Clint Eastwood) calls himself Monco in this film. "Monco" is Italian for "one handed" or "one armed", which is pretty appropriate considering his habit of fighting, drinking, etc with his left hand only. His right hand always remains on his gun underneath his trademark poncho.

Although Clint Eastwood's poncho was never washed during the production of the "Dollar" trilogy, it was mended. In the final scene of Per un pugno di dollari (1964), the poncho is pierced by seven bullets from Ramon's Winchester. In the sequel, Eastwood wears the same poncho back-to-front and the mending of the bullet holes is clearly visible in several scenes. The mended area, originally on the left breast, is now worn over the right shoulder blade.

"Monco" is NOT the same character as "Joe" in Per un pugno di dollari (1964). This was the finding of an Italian court that adjudicated the lawsuit brought by Jolly Films, producer of "A Fistful of Dollars". After the release of the first film, director Sergio Leone had a falling out with the producers and made this sequel with a different producer, 'Alberto Grimaldi'. Jolly Films sued, claiming ownership of the "Joe" character, but lost when the court decided that the western gunfighter's persona, characterized by the costume and mannerisms, belonged to the public domain's folklore.

Sergio Leone also considered Robert Ryan for the role of Col. Mortimer, being a fan of his performance in The Naked Spur (1953).

On its 1969 re-release it was double-billed with "A Fistful of Dollars."

Continuity

After Monco's cigar is shot to a very short length by one of Indio's gang, subsequent shots have it both longer and then shorter again.

When Monco and Mortimer are loading their guns, getting ready for the final showdown, they have a few bruises on their faces from their beating. Once the shootout begins, they no longer have any bruises.

When Mortimer unrolls the wanted poster before sliding under the door, the poster has a curled-up appearance. Once it's under the door inside the wanted man's room, it is completely flat.

When Monco enters the saloon at White Rocks, his hat and poncho are dripping wet. In the next shot, they are totally dry.

During the poker game between Monco and Cavanaugh, in some shots there are just two poker hands on the table, and in other shots there are four.



Factual errors

When Monco's hat is shot off his head and down the street by Mortimer, ricochet sounds are heard; this would happen only if bullets hit solid objects like metal. (This distorts the bullet and causes it to bounce off and tumble, which causes the characteristic whine.) In fact, most shots are accompanied by the sound of ricochets.

When Manco rejoins Indio's gang breaking into the stolen safe, the valley they are in has numerous date palms. Although some date palms were imported to California and Arizona, there weren't any in New Mexico, and none were in use until the 1900s.

Col. Mortimer (Lee Van Cleef) is browsing a newspaper (El Paso Tribune) with the publication date of Monday June 15 1872. The actual day of June 15 1872 was Saturday, not Monday.

When Mortimer comes into the saloon looking for Guy Callaway, the piano player is performing in the Stride style, which wasn't invented until the 1920s.

In both dream scenes, Mortimer's brother-in-law was shot three times at close range. There are no bullet holes front and back or in the wall behind him.



Incorrectly regarded as goofs

When Mortimer is browsing in the local newspaper all pages are identical. He was browsing in the tear sheets of the newspaper's morgue where they keep back issues. They were bound in hardcovers. There was more than one copy of each.

The young man whom Indio kills in the flashbacks is shot three times, yet there is no evidence of bullet holes or blood. However, this is because it is Indio's memory and not an actual shooting.

Face on wanted poster of Indio is a high-contrast reproduction of a modern style photo. Indio's high-contrast repro is obviously a continuation of the previous shot of his insanity face. This is Artistic License.

Indio's image on his wanted poster looks exactly like him, but the face on the wanted poster of Guy Callaway, Mortimer's first target - looks nothing like him. It was never explicitly stated in the movie that the man shot by Mortimer was actually Calloway, not even when the bounty was paid, and he clearly did not look like Calloway.

When Monco returns from his Santa Cruz junket (at around 1hr 10 mins), he passes by the offices of the "Gazzette" on his left. An American newspaperman would use "gazette"; "gazzette" (plural) is Italian. "Gazzette" is also a Spanish word and could easily be correct, used so close to the Mexican border.

Revealing mistakes

While breaking Indio out of jail, one of the bandits shoots a prison guard, who reacts to the bullet before he is shot.

During the "Hat Duel", both Monco and Mortimer shoot each other's hat numerous times. However, when they are talking in Mortimer's hotel room afterwards, their hats are sitting on a table, and only one bullet hole is visible in each.

After Monco rides into Agua Caliente, he shoots some apples off a tree for a little boy. This cements Indio's suspicion that he's not ruthless enough for a bandito, so he must be a bounty killer.

As Monco is riding away from the sheriff's office, just after the 18 minute mark, the house to his left shows a view through a side window to daylight, revealing that the building has no roof and is just a set.



Anachronisms

The car seen driving down the dirt road is visible during the conversation from the passenger on the train. This occurs before Mortimer lowers the Bible, when the traveling salesman says the train does not stop in Tucumcari. The car is seen in the distance, moving from lower right to upper left and driving at high speed.

In the hilarious scene where Monco and Mortimer shoot each other's hats, the lights of an airplane can be seen flying over Monco's head in one quick shot.

Tucumcari wasn't founded until 1901.

Mortimer smokes a meerschaum pipe throughout the movie, which is historically accurate; however, the pipe stem is obviously Lucite, a plastic first marketed in 1933. An 1860s pipe stem would be carved of amber, ivory, antler, or bone.

When searching old newspapers to determine who is competing with him in El Paso, Colonel Mortimer discovers a front page of the El Paso Tribune from June 15, 1872 with a story about Monco that includes a photograph. The first photograph printed in a newspaper would not occur until March, 1880. In addition, the headline above the photo is of a modern brush-style linotype font.



Crew or equipment visible

As Indio tells the story of the safe to his men, a crew member wearing a light blue shirt entering the left side of the frame can be seen in the background in one of the close-up shots of Nino.

When Monco rolls Groggy over with his boot after killing him, the fake blood capsule that Luigi Pistilli used for his death scene can be seen. Clint Eastwood steps on it with his boot to hide it.



Errors in geography

An unrelated map of Uruguay is seen hanging on the wall in Tucumcari's Sheriff's Office around the 12:00 minute mark. Uruguay has nothing to do with the film and lies thousands of miles away from Tucumcari.

There are no cacti visible. Cacti are found only in North and South America, making it obvious that this was filmed in the Old World; in this case, Spain.



Character error

There is no way the baby shown is 18 months old, perhaps a year old at most.