The logo seen on the T-shirt of Rick's son Carl is that of another Robert Kirkman creation, Science Dog.
The Dixon brothers, T-Dog, Jacqui, as well as Morales and his family are not characters in the comic book, although they are each featured prominently in season 1 of the TV series.
Carol's husband never appears in the comic, he is only mentioned to have been killed.
Out of the 20 characters at the camp, only 10 are actually in the comic (Rick, Lori, Carl, Shane, Carol, Sophia, Jim, Dale, Andrea, Amy and Glenn).
SPOILER: In the comic, Lori and Shane's affair was only a one night stand instead of a regular occurrence and is revealed in issue 5, while in the show in the 2nd episode.
The story takes place during the "Days Gone Bye" (which the pilot is also called) arc (issues 1-6).
The word "zombie" is never used. The zombies are either referred to as "Walkers", "Geeks", "Skanks", and to the CDC, "Test Subjects". In season 2 the terms "Roamers", "Lurkers", and to Hershel, "People", and "Lame Brains" are added. In season 3 "Biters" was introduced to the lexicon.
"Walking Dead" creator Robert Kirkman was on the set throughout the filming of the first season.
This is the second AMC show to feature an RV. Walking Dead utilizes a Winnebago Chieftain, while in Breaking Bad, a Fleetwood Bounder is used throughout the show.
The name Edwin Jenner, the doctor at the CDC, is a reference to Edward Jenner who developed the first vaccine (which was for smallpox).
During lunch breaks, the zombie cast would eat together while the human cast ate together.
Actors who played zombies had to go through zombie school to learn how to walk and move like zombies.
In an online interview, it was revealed that Frank Darabont envisioned having several self-contained episodes that would not continue the main story. One such episode would have been the season two premiere. It would have involved Sam Witwer (who Darabont used in The Mist (2007) and played the tank zombie in the series premiere) as a solider in a Black Hawk Down style Atlanta. Witwer would have encountered several of the cast before being bit and locking himself in the tank.
The show is being made into a haunted house at Universal's "Halloween Horror Nights" in Orlando Florida, and a Maze in Universal's Halloween Horror nights Hollywood for their 2012 event.
For Season 3, the make up team used darker skin tones for the Walkers to show further decay as time has progressed.
All of the principal actors have a "Last Supper" the day they film their death scenes.
The tank which Rick hides in is a Chieftain Mk.10, the same model actor Kevin Spacey purchased at a military auction to use on his ranch near Medicine Hat, Alberta.
It took 3 hours to get the makeup on the "Bicycle girl" zombie. to get the her to look like she was missing her lower torso they used blue pants to be removed in editing.
In the first episode of the first season, when Grimes beats his first zombie to death with a baseball bat the blood splatter on his shirt resembles a smiling skull.
During the scenes in the survivors' camp, Lori and Carl are never identified by name. Followers of the graphic novels would have known who they were, but for viewers who never followed the graphic novels, they would have had to be paying close attention when Rick took his family photo out of his squad car to know that the woman and boy in the camp were Lori and Carl. When it became clear that Shane was having a sexual relationship with Lori, the viewer who was new to the story likely would not have realized that she was Rick's wife.
Rick Grimes' home in fictional King County, Georgia is actually a house located directly across the street from Zoo Atlanta. In fact, when Grimes exits the house, you can just see one of the zoo buildings through the trees on the other side of the street.
Many of the locations used for fictional King County, Georgia are located in Atlanta's Grant Park neighborhood, the same neighborhood used as locations for the movie "The Blind Side" which also featured "The Walking Dead" actor IronE Singleton.
When Rick first leaves the hospital and walks up the grassy hill, several grounded Army helicopters can be seen. These bear the markings of the 7th Cavalry Regiment, General Custer's command at the Battle of the Little Bighorn (commonly referred to as Custer's Last Stand).
During filming of this episode, when Merle Dixon (Michael Rooker) is shooting from the rooftop of the department store, The S.W.A.T. squad of Atlanta were called because people thought he was a sniper. But everything was fine when they were told they were filming.
SPOILER: The construction company whose truck Rick and Glenn steal to get the other survivors out of Atlanta is "Ferenc Builders". Ferenc is series developer/writer Frank Darabont's given first name.
Legendary songwriter Craig Wilde (Craig Braginsky on IMDb) did a walk on as a zombie. It is the 4th time he has played an uncredited zombie.
During filming of the scene where Merle Dixon (played by Michael Rooker) is shooting walkers from the roof of the building, civilians on the street heard the sound of the fake rifle and called the police as the thought it was a terrorist attack. SWAT teams were called in.