Disney turned down making the film, claiming the mother/son relationship was "too risque".
Originally, a nuclear explosion was supposed to be the element that would be required to send Marty back in time. However this idea was scrapped because the shooting of the scene would cost too much for the budget of the movie.
Melora Hardin was originally cast to play Jennifer; she was let go when Eric Stolz was replaced by Micaehl J. Fox; because of her height. Melora was much taller than Michael J. Fox, and the director thought they would look odd together.
When Martytravels to 1955 he land's at Mr. Peabody's farm, who calls his son Sherman. This is a reference to the time-travelling duo from The Rocky & Bullwinkle Show.
The amp which Marty destroys at the start of the movie is labelled 'CRM-114'. This is the serial number of the Jupiter Explorer in '2001: A Space Odyssey'.
The amplifier that Michael J Fox blows up at the beginning is labelled 'CRM-114'. This is a reference to Dr. Strangelove, in which the B-52 crews receive their orders over a CRM-114.
Marty goes forward in time to November 5. This is the same date that HG Wells goes to in 'Time After Time'.
In the battle of the bands scene, when Marty introduces The Pinheads, Huey Lewis; who provided "The Power of Love" for the film's soundtrack; plays the judge who says, "You're just too darn loud."
As Marty and Jennifer are walking across the car park after the auditions, the car in the end spot registration plate reads FOR MARY after the wife of one of the crew.
The original design for the time-machine was to be in the form of a refrigerator.
Near the beginning of the movie Back To The Future there's a scene where they show all of the clocks at Doc's house. If you look closely there is one clock with a little man hanging from the minute hand
When Marty visits George in his radiation suit in the middle of the night, he says that he is an extra-terrestrial from the planet Vulcan and does the Vulcan salute. Planet Vulcan is the planet that Star-Trek's Spock comes from.
When Marty is in 1955, he dresses up in his radiation suit and visits George in the middle of the night. In 1985, when George receives the new book that he wrote called "A Match Made In Space", you can see a guy in a radiation suit on the cover of the book that looks exactly like how Marty looked like in a radiation suit in 1955.
When Marty leaves 1985, the mall that he was located in when time-traveling was called the "Twin Pines Mall". When he travels back in time to 1955, he knocks down a tree and then when he comes back to 1985 the mall is called the "Lone Pine Mall".
All of Michael J. Fox's singing in the movie is done by musician Mark Campbell.
Originally Eric Stoltz was supposed to play Marty McFly. However after a few scenes were shot, the directors thought that he wasn't the right actor for the job. And so they later asked Michael J. Fox, who of-course accepted the offer.
Huey Lewis didn't just contribute its theme song "Power of Love" to the film, Lewis was featured in an uncredited cameo as one of the critics that declined Marty McFly's band from the upcoming school prom at the start of the movie.
After the decision to replace Eric Stoltz had been taken, an arrangement was made with the producers of Family Ties, wherein Michael J Fox could work on Back to the Future, although he would only be available at night time and weekends.
Although the film's creators always wanted Michael J Fox to play Marty, they originally had to cast Eric Stoltz because of a scheduling conflict with Family Ties. They spent approximately two weeks shooting with Eric Stoltz as Marty.
There are only about 32 special effects shots in the entire film.
The production ultimately used three real DeLoreans.
In the shot of the clock tower of 1985, after Doc Brown sent Marty into the future (with a flying-by helicopter), you can clearly see that the piece of the ledge under the clock dial is broken off. It was broken off by Doc Brown in 1955.
The set for Hill Valley is the same one used for the film 'Gremlins'. Both movies were filmed in the Universal Studios backlot.
The man driving the jeep that Marty hangs on to at the beginning of the movie is stunt coordinator Walter Scott.
At the start of the movie, the mall where Doc and Marty meet up in the parking lot is called 'Twin Pines Mall' due to the area once belonging to a man who bred pine trees. When Marty goes back in time, he takes out one of two pine trees making his escape from the farmer there. When Marty goes back to the future, the mall's name is now 'Lone Pine Mall'.