Terry Jones spent most of the budget on the "Every Sperm Is Sacred" sequence. The rest of the team found out later.

Sensitive to the young actors in the "Every Sperm is Sacred" scene, Sir Michael Palin actually said "those little rubber things on the end of my sock." The word "cock" was dubbed in later.

The kids who sang in the "Every Sperm is Sacred" sketch later said they had no idea what they were singing about.

"The Crimson Permanent Assurance" segment was filmed as if it were a completely separate project. Terry Gilliam got his own soundstage, crew, and cast. This segment continued to expand because, according to Gilliam, nobody told him to stop.

Graham Chapman, who was openly gay, asked to play God in this movie because he was frustrated at the Church of England for refusing to marry him and his partner, David Sherlock. At the time, same-sex marriage was not legal in the United Kingdom, nor recognized by the Church of England.

Continuity

In the war sequence, the soldiers give their sergeant a clock, which is placed on the edge of the mound they are hiding behind, clearly visible. In the next shot, the clock is gone.

In the classroom scene, the young student seated in the rear right corner appears and disappears three times.

At the start of the miracle of birth section, the mother is traveling head first. Just before she leaves the corridor, the shot from the gurney indicates that she is moving feet first.

Mr. Creosote vomits onto the floor, and only little traces can be seen on the shoulder of his suit jacket. After the guests are seen looking shocked, before the waiter shows him the menu, there is much more vomit on his shoulder than before.

During the shot of Mr. Creosote inflating, some of the extras on the right hand side of the screen can be seen behind him. After the explosion, many of the same extras can be seen in one shot being hit by Mr. Creosote's entrails, but once the explosion is clear, they are again behind him, but free of any of the viscera that they were previously splattered in.



Revealing mistakes

In the death sequence, the name at the top of the mausoleum is "nitruc" instead of "curtin", so the segment is reversed/flipped.

In the "Live Liver Donation" scene, John Cleese is clearly chuckling at the performance of his two fellow Pythons.

When Mr. Creosote throws up for the first time in the movie, traces of vomit can be seen on the floor prior to his vomiting, presumably leftovers from previous takes/rehearsals.



Anachronisms

The Anglo-Zulu War scene is set in 1879, when wearing a mustache was mandatory in the British Army. Despite this, some of the soldiers (like Terry Jones's character) are seen without a mustache.



Crew or equipment visible

In the vomiting scene, the end of the hose the liquid comes out of is visible right after the bucket is taken away.



Boom mic visible

When The Grim Reaper talks to the couple and their dinner guests, the boom mic moves along the fabric ceiling.



Character error

The organ harvester tells the man's widow that he has to be dead to donate his liver. While the man will almost certainly die from being cut open the way the way he was, one doesn't need to be dead to donate their liver. Unlike other internal organs, the liver can regenerate lost tissue, so he could have donated half of his liver and survived.

In the WWI scene, the officer is called Captain Biggs, but he only has 2 pips on each sleeve, denoting the lower rank of Lieutenant.