"The Dirty Dozen" author E.M. Nathanson may have gotten the idea for the title (if not the plot) of his best-selling novel from a real-life group of World War II 101st Airborne Division paratroopers nicknamed "The Filthy Thirteen." These men, demolitionists in Headquarters Company of the 506th Parachute Infantry Regiment of the 101st, supposedly earned their nickname by not bathing or shaving for a long period of time during training prior to the Normandy invasion. Members of The Filthy Thirteen can be seen in famous vintage film footage and still photos, their faces painted with Indian "war paint," before boarding their planes for the D-Day jump.

Jack Palance turned down the Telly Savalas role because he disapproved of the character's racist overtones.

Lee Marvin (Marines), Telly Savalas (Army), Charles Bronson (Army), Ernest Borgnine (Navy) and Clint Walker (Merchant Marine) all served in World War II.

Lee Marvin referred to this movie as "crap" and "just a dummy moneymaker", although he enjoyed the film. The movie has nothing to do with war, he stressed, and he was very pleased that he got to do The Big Red One, which mirrored his own wartime experiences.

John Wayne was first offered the part of Maj. John Reisman, but he declined and went on to star in and direct another war film (The Green Berets). The part was then offered to Lee Marvin, who took it. Wayne's refusal was due to his disapproval of the original script where Reisman has a brief affair with a married woman whose husband is fighting overseas.

Charles Bronson's character says his father was a coal miner from Silesia (Central Europe). In real life, this is true. Charles Bronson's real father was a coal miner from Lithuania.

Donald Sutherland was a late casting decision, replacing an actor who dropped out because he thought the role was beneath him.

Robert Aldrich was told that he could be in line for an Oscar as Best Director for the film if he cut out the scene of Jim Brown dropping hand grenades into the bomb shelter. The scene was considered controversial because the Germans (including women) were locked inside the bunker and had no chance to survive. Aldrich considered it but elected to leave the scene in to show that "war is hell".

Jim Brown's character is credited as 'Napoleon Jefferson' in the original US trailer.

Although Robert Aldrich had tried to purchase the rights to E.M. Nathanson's novel "The Dirty Dozen" while it was still in outline form, it was MGM that successfully acquired the property in May 1963. The book became a best-seller upon its publication in 1965.

As film production ran over-schedule, Frank Sinatra advised 'Trini López' to quit so that his recording career wouldn't lose it's momentum or popularity. So Lopez took Sinatra's advice and quit. (Or, according to another account, his agent unwisely demanded more money, which Robert Aldrich refused to grant. Originally, Lopez's character, Jimminez, was supposed to be one of the heroes. He was to be the one to ignite all of the dynamite that would destroy the entire chateau. But with Lopez's abrupt departure, his character was written off as being killed during the parachute jump.

Construction of the faux chateau proved *too* good. The script called for it to be blown up, but the construction was so solid that 70 tons of explosives would have been needed to achieve the effect! Instead, a section was rebuilt from cork and plastic.

During the "Last Supper" scene, Maggot (Telly Savalas) is in the Judas position of the Leonardo Da Vinci painting, before betraying the team during its mission.

MGM's biggest moneymaker of 1967.

Production on the film ran for so long that Jim Brown was in danger of missing training camp for the up-coming 1967-68 football season. As training camp and the NFL season approached, the NFL threatened to fine and suspend Brown if he did not leave filming and report to camp immediately. Not one to take threats, Brown simply held a press conference to announce his retirement from football. At the time of his retirement, Brown was considered to be one of the best in the game and even today is considered to be one of the NFL's all-time greats.

Stars from this movie George Kennedy, Clint Walker, Ernest Borgnine and Jim Brown were reunited to play the voices of the soldiers some thirty-one years later in Small Soldiers.

The character of Reisman (Lee Marvin) was based on John Miara of Malden, Massachusetts, who was a close personal friend of Marvin's while both were serving in the Marine Corps during WW II.

The French chateau that appears in the film was constructed especially for the production by art director William Hutchinson and his crew of 85. One of the largest sets ever built, it stood 240 feet across and 50 feet high. Gardeners surrounded the building with 5400 square yards of heather, 400 ferns, 450 shrubs, 30 spruce trees and 6 full-grown weeping willows.

The operation count-off is as follows: - One: down to the road block we've just begun - Two: the guards are through - Three: the Major's men are on a spree - Four: Major and Wladislaw go through the door - Five: Pinkley stays out in the drive - Six: the Major gives the rope a fix - Seven: Wladislaw throws the hook to heaven - Eight: Jiminez has got a date - Nine: the other guys go up the line - Ten: Sawyer and Gilpin are in the pen - Eleven: Posey guards points Five and Seven - Twelve: Wladislaw and the Major go down to delve - Thirteen: Franko goes up without being seen - Fourteen: Zero hour, Jiminez cuts the cable Franko cuts the phone - Fifteen: Franko goes in where the others have been - Sixteen: we all come out like it's Halloween

The scene where one of the dozen pretends to be a general inspecting Robert Ryan's troops was initially written for Clint Walker's character. However, Walker was uncomfortable with this scene, so Robert Aldrich decided to use Donald Sutherland instead. The scene was directly responsible for Sutherland being cast in MASH, which made him an international star.