During the exposition, the pronunciation of Kharis's name goes from "KHA-ris" to "Kha-RISS" to "Kha-REECE," with even the same actors (George Zucco and Eduardo Ciannelli) using multiple pronunciations.
Professor Andoheb has Marta strapped to a stone table. In one shot, Marta is lying on the table without the straps, but in the next shot the straps reappear.
In Kharis' tomb after Dr. Petrie is killed, Steve and Babe go running into the tomb and Dr. Petrie's body is obviously not on the floor. A few seconds later, Babe looks down and sees Dr. Petrie's body on the floor next to the table.
When Steve is examining the beggar's medallion, he is holding it in his left hand, yet in the close up it's being held in his right hand.
After they discover's Ali's body in the tent, Babe and Marta are sitting down in front of the fire. Marta has her head buried in her hands, as Steve starts to sit down beside her, she raises her head twice. Seconds later, Steve clearly calls her "Marla."
A little before 15 minutes into the movie, Professor Andoheb refers to "the Inca ruins in Mexico", yet the Incas never were in Mexico. In reality, the Incas were centered in Peru with their empire stretching from Ecuador to northern Chile.
The revolver can shoot more than six shots because it is a trick revolver as stated by Marta before she goes to visit Steve and Babe to get her father's money back.
In the ancient Egypt flashback when Kharis is caught as he is about to bring the princess back from the dead, the scene cuts back and forth between close-ups of him in which his arms are folded across his chest and wide-angle shots wherein they are straight down along his sides. This is because the latter are stock footage from The Mummy (1932), featuring Boris Karloff as the offender.
In the bar fight, an actor in the scene is thrown against a wall, causing it to move briefly about 4-5 inches apart from where it joins the adjacent section.
When the two adventurers are about to explain how to make money in Egypt to the magician, the lips & jaw of Steve Banning (in profile) don't move when he tells Babe to not tell the magician about their scheme.
When the Priest is first coming down off his throne to show his successor the ancient secret, his lips don't move as he tells his successor to follow him to the viewing portal.
After the mummy places Marta on the stone slab, the Priest starts to speak to tell the mummy where to go next to get more life-giving fluid, but his mouth doesn't move in the long shot - only in his close up right after.
Two of the actors have their names misspelled in the credits. Cecil Kellaway is spelled Kelloway and Eduardo Ciannelli is spelled Cianelli.
When the archaeologists are discussing the well preserved Mummy, one remarks that he was embalmed very well. Since Karris was buried alive, he was not embalmed. But at this point in the film, they couldn't have known that.
As the High priest is about to give the mummy his Fluid from the Tana leaves , if you look closely , you can see him pucker his lips.
When Marta says, "I'll fix him with my trick revolver," her lips do not move.
They used Bactrian Camels (two humps) in the film as opposed to Dromedary or Arabian Camels (single hump) that are native to northern Africa.
The film explains in some detail how the mummy Kharis is kept alive by administering a brew of Tana leaves each month on the full moon. The leaves are kept in a sacred box, containing at most a few hundred leaves. This simply would not be enough to have kept Kharis alive since antiquity, given that at least one leaf each month would be required for at least three thousand years.
How was it that Kariss was not only able to sneak into Steve Bannings tent without anyone seeing him , but also after nearly killing Marta's father , grab her , get out of the tent , get her to the sacrificial chamber and back out to follow Steve all within a matter of a few seconds .
The slaves who buried Kharis are then killed to keep the burial site secret. However, Kharis is then dug up by the priests and reburied in a cave, where his body is later found. Why wouldn't the slaves have just buried Kharis in the cave in the first place.
After Marta screams, and Steve and Babe discover the Mummy's second victim, the shadow of the boom mic is visible on the wall of the tent behind them.
Dr. Petrie contradicts himself by stating that the lines on the face mean that the mummy was buried alive, but then states that this is the best example of embalming he has ever seen.
Despite what the movie says, at least two people (including the stage actress Margaret Culting) have learned to talk without a tongue. In fact, Ms. Culting is said to have had perfect diction.