The United States military refused to lend Francis Ford Coppola any military equipment, due to the order to "kill Colonel Kurtz". Coppola instead had to borrow local military equipment.
Shooting, originally scheduled for six weeks, took 16 months.
The canteen scene with Lieutenant Colonel Kilgore and the wounded Viet Cong is based on an actual wounded VC fighter who fought while keeping his entrails strapped to his belly in an enameled cooking pot. The incident was documented by the photojournalist Philip Jones Griffiths. The real-life U.S. soldier was quoted as saying, "Any soldier who can fight for three days with his insides out can drink from my canteen any time!"
More than a year had passed between the filming of Willard and Chef searching the jungle for mangoes and encountering the tiger, and the immediately following shots (part of the same scene) of Chef clambering back onto the boat, ripping off his shirt and screaming.
Laurence Fishburne was 14 when production began in 1976. He lied about his age, a common practice for men under 18 during American wars.