Rex Allen Sr., 78, a film and television actor and singing cowboy who also narrated films and cartoon features, died Dec. 17, several hours after his caretaker accidentally ran him over with a car, police said. He was pronounced dead at a hospital here.

A police spokesman said they believed the caretaker did not realize Mr. Allen was behind the car when she began to back it up in Mr. Allen's driveway. Detectives were trying to determine whether Mr. Allen had fallen before he was hit, the spokesman said.

Mr. Allen, who was billed as the Arizona Cowboy, made more than 20 films for Republic Studios, which had previously made stars of Gene Autry and Roy Rogers. He was supported in many of his pictures by stars Buddy Ebsen and Slim Pickens.

He made his movie debut in 1949 in "The Arizona Cowboy." His other films included "Under Mexicali Stars" (1950), "The Old Overland Trail" (1952), "Down Laredo Way" and "The Phantom Stallion" (both in 1953).

On television, he was the star of "Frontier Doctor" in 1958 and appeared on many variety shows. His voice became familiar to millions when he narrated a series of 80 Walt Disney wildlife films in the 1960s. Later, Mr. Allen concentrated on television and radio voice-overs for commercials and also narrated the 1973 animated feature film "Charlotte's Web."

Mr. Allen, whose signature stallion for the western movies was Koko the Wonder Horse, grew up on an Arizona ranch.

He got into music before reaching his teens, playing guitar and singing with his fiddle-playing father at dances. His professional break came in the 1940s, when country star Roy Acuff heard him with a band in Quakerstown, Pa.

Mr. Allen joined with the National Barn Dance on WLS in Chicago and subsequently was signed by Mercury Records. His hits included "Streets of Laredo" and "Crying in the Chapel."