Noah Hathaway was hurt twice during the making of the movie. During his horse riding training he was thrown off a horse which then stepped on him. Then during the shooting of the drowning sequence in the "swamp of sadness" his leg got caught on the elevator and he was pulled under water. He was unconscious by the time he was brought to the surface.
Noah Hathaway almost lost an eye during the fight-scene versus Gmork. One of the claws on his giant paws poked him in the face. The robot was also so heavy that he lost his breath as well when he was hit to the ground by it. They only made one shot due to the risk that he would get seriously wounded.
Tami Stronach was attending theatre classes in San Francisco when she got the audition to be The Childlike Empress. Her acting teacher was friends with the production executive and talent scout Anna Gross. Tami initially believed she was auditioning for a little play and had no idea it was to be for a major motion picture.
The Night Hob says a profanity in the opening scene where the Rockbiter appears running down all in its path. This profanity is often dubbed over by the grumble of the Rockbiter's scooter, so that it can be shown as a children's film.
Author Michael Ende decided that he was unhappy with the film's version of his story, and refused to have his name placed in the opening credits. A small credit appears at the end with his name. He also asked if the movie title would be changed or cancelled. After the studio declined both options, he filed a lawsuit and ultimately lost.
Author Michael Ende felt that the movie did not follow closely to the book that he urged that production be shut down or the title of the movie be changed. Because the producers refused to do either, Ende filed a lawsuit against the producers. He ended up losing the case.
Noah Hathaway was due to appear in the Broadway show "Chaplin" alongside Gene Kelly and Ann Margaret, but opted to do "The Neverending Story" instead. He had been cast in the film, then the original director was fired, and when Wolfgang Petersen was hired, Noah was immediately re-hired.
Two scenes from the book were written in the script but ultimately scrapped due to special effects limitations. The first was the initial appearance of Falcor, where Atreyu rescues him from Ygramul the Many, a swarm of poisonous wasps taking the form of a giant spider. This is where Bastian's scream being heard by the characters in the book was to have taken place, and also explained why Atreyu and Falcor are later seen being given medicine by the Gnomes. The second cut scene involved Atreyu and Falcor encountering the Wind Giants, giant creatures made of clouds, and being caught in a fight between them. This was re-edited into their close encounter with the Nothing before Atreyu falls into the sea.
Contrary to Internet rumor, the horse did not really die during the filming of the Swamp of Sadness scene. As confirmed by German magazine interview with Noah Hathaway shortly after the movie, and in the years since at conventions, the horse was given to Noah at the end of filming but due to the cost of transportation, need for quarantine, and sterilization, the horse was left behind in Germany.
"The Childlike Empress" was just child-"like". She has existed for as long as there have been stories to tell. She was portrayed by Iranian born dancer Tami Stronach who was only 11 years old when the production started.
The name of the mystical land in (the English translation of) the original novel was Fantastica, not Fantasia, but the original German name Phantásien translates more accurately into English as Fantasia.
During filming in Germany, because it was an unusually hot summer one of the statues of the Ivory Tower actually melted. On other days, the crew were forced to shut down production because the blue backgrounds for the matte work refused to operate properly.
When Warner Bros. passed on releasing Supergirl (1984), which was originally designed to be their tent pole release that year, they hurried the release of Die unendliche Geschichte for summer audiences.