John Carpenter had a good working relationship with James Woods on set. Apparently Woods has a reputation for being difficult to work with, but Carpenter got along with him just fine. They had a deal: Carpenter could film one scene as it was written; the other Woods could improvise. Carpenter found to his delight that many of Woods' suggestions were brilliant.
When Largo Entertainment approached John Carpenter with this project, they gave him two scripts, one by Don Jakoby and another by Dan Mazur. Carpenter read the scripts and the novel and saw a potential in the movie that he had been interested in, which was to do a western disguised as a horror film. So Carpenter and friend Larry Sulkis worked together to create a new screenplay, taking elements from both Jakoby's and Mazur's scripts, the novel, and some of their own ideas. Jakoby, for whatever reason, received sole writing credit.
For this film, John Carpenter wanted to stay away from the stereotype of gothic vampires and wanted to make his vampires "savages" and not be "brooding loneliness in their existence. They're too busy ripping and tearing humans apart."
Just before production began the studio cut the budget by 2/3, and the filmmakers had to furiously rework the story to fit. According to John Steakley, who wrote the novel, the finished film contained much of his dialogue and none of his plot.
Producer and John Carpenter's wife Sandy King cast Thomas Ian Griffith as Valek because they both wanted "someone who looks formidable, but is also alluring. There always has to be something alluring about the evil nature of the vampire."
John Carpenter cast James Woods because he wanted his character Jack Crow "to be as savage as the prey he's going after." Woods himself took interest in the project because it was something different for him.
There are many similarities with this and another vampire film made the same year, Blade (1998). Both are about a vampire killer, and they both have a similar plot of vampires trying to complete an arcane ritual that would allow them to move about in daylight. They also both feature a female character slowly turning into a vampire throughout. In addition, Tim Guinee appears in both films.
Alec Baldwin had briefly accepted the role of Montoya before declining it early into pre-production and passing it onto his brother, Daniel. John Carpenter had not seen any of Daniel Baldwin's work and had the actor read for him.
According to STARLOG magazine, Cary-Hiroyuki Tagawa was unhappy with his role in the film. He tried speaking to John Carpenter several times about his character's back story and motivation, but Carpenter rebuffed him. This left Tagawa feeling like he was little more than a glorified stuntman.
The MPAA took issue with the film's over-the-top violence, threatening to give it an NC-17 rating unless some of the gore was cut. Sandy King said, "We satisfied the ratings board by just cutting short of a few things that went into really gruesome stuff."