Director Terry George had Don Cheadle in mind for the lead part from the beginning of his involvement. During pre-production, potential investors and interested studios wanted Denzel Washington, Wesley Snipes, Mekhi Phifer and even Will Smith because of their suggested bigger drawing capacity at the box office. But due to ultimately producing the film independently and coming up with the money himself, George was able to go back to his original choice.
Nick Nolte's character (Col. Oliver) is modeled in part on Lt. Gen. Roméo Dallaire, the Canadian commanding officer of the UN Peacekeeping mission in that country who attempted to interfere with the Rwandan Genocide despite his superiors' indifference to the atrocity. Dallaire was also the subject of Sundance audience award documentary Shake Hands with the Devil: The Journey of Roméo Dallaire (2004), and witnessed such horrible acts in Rwanda that he later suffered severe post-traumatic stress disorder. Despite these facts, this is the only fictional character (name and facts) depicted in the film.
The real Paul and Tatiana went back to Rwanda with the director for research. Many people came to welcome them at the airport.
The screenwriter spent one year writing the first draft of the script. During the process, he called the Rwandan embassy in DC. The woman who picked up the phone was a survivor who stayed at the Milles Collines Hotel.