K-9

Although Jerry Lee is credited as playing himself in the opening credits, he was in fact played by multiple dogs during the shoot.

The primary dog was named Rando, a three-year-old German Shepherd. A two-year-long search was held to find the right dog for the role and over forty dogs were considered. Eventually, four young Shepherds were brought from West Germany and trained for three months with Karl Lewis Miller. While typical dogs can understand 10-15 commands, Rando was able to perform anywhere from 125 to 150 actions.

A separate dog that was used as a stunt double for some scenes was named Koton, and was a real-life police dog with the Kansas City Police Department who was sadly killed in the line of duty in 1991, which has led to some confusion that "the dog from K-9" was killed while on duty.

After Jerry comes out of the car wash, Dooley opens the door and water spills out, but when Dooley gets into the car and leans back against the car seat, his jacket does not show any wetness when he leans forward again as he is pulling out of the car wash.

Jerry Lee is played by Rando, not Jerry Lee, as credited at the end.

The UK theatrical version was cut by 21 secs to secure a "12" rating and removed descriptions of a "Colombian Necktie". The 15 rated video version was uncut and the 12 rated DVD is also intact.