Despite some credit listings, Natividad Vacío plays Miguel, not Tomas, and John A. Alonzo (billed as John Alonso) plays Tomas, not Miguel.
It never clearly shown just how many people each member of the Seven kill. However, if one were to look at clear cases on onscreen killings, Vin (Steve McQueen) has the most, while Harry (Brad Dexter) has no onscreen killings.
It was Yul Brynner who approached producer Walter Mirisch with the idea of doing a Western adaptation of Akira Kurosawa's classic, Shichinin no samurai.
Mexican censors required the peasants to always be wearing clean clothes.
O' Reilly (Charles Bronson) is the last of the Magnificent Seven to die. O' Reilly's counterpart in Shichinin no samurai is the first of the Seven to be killed.
Pay close attention to Eli Wallach whenever he handles his gun. Whenever he puts the gun back into his holster, he always looks down at it. That was because Wallach wasn't used to drawing the weapon and didn't want to look foolish by missing the holster while putting his gun back, as Wallach would admit in the DVD Documentary.
The "bandit gang" hired for Calvera adopted Eli Wallach as one of their own. In the mornings before shooting started, but after Wallach was in costume, he and the group would go riding together for an hour. Additionally, members of the gang insisted on doing the final checks for Wallach's horse tack and prop gun before he was allowed to use either.
The 1967 hit song "Sweet Soul Music," written by Arthur Conley and Otis Redding and first recorded by Conley, quotes a portion of Elmer Bernstein's score for The Magnificent Seven as its instrumental horn opening.
The film was cast quickly to beat an actor's strike.
The first in the original series of four "Magnificent Seven" movies.
When filming began in Mexico, problems arose with the local censors, who demanded changes to the ways that the Mexican villagers would be portrayed. Walter Newman, who had written the screenplay, was asked to travel to the location to make the necessary script revisions, but refused. The changes written in by William Roberts were deemed significant enough to merit him a co-writing credit. Newman refused to share the credit, though, and had his name removed from the film entirely.