"Requiem for Methuselah" is a third season episode of the original science fiction television series, Star Trek, first broadcast on February 14, 1969. Its repeat broadcast, on September 2, 1969, was the last official telecast of the series to air on NBC (Star Trek would immediately debut in syndication on the following Monday, September 8, a full three years after its debut). It is episode No. 74, production No. 76, written by Jerome Bixby and directed by Murray Golden. It guest-stars James Daly as "Mr. Flint", and Louise Sorel as "Rayna Kapec" ("Kapec" is an anagram of Capek, after Karel Čapek, who introduced the term robot).

In this episode, the crew of the Enterprise encounters an immortal human.

The crew of the Federation starship USS Enterprise is struck with deadly Rigellian Fever. They arrive at the remote planet Holberg 917-G in search of the mineral Ryetalyn, used to manufacture a cure. Sensors detect no humanoid life.

Captain Kirk, first officer Spock and medical officer Dr. McCoy beam down to the planet to investigate and are attacked by a robot. The robot is called off by its master, who identifies himself as Flint. Flint claims that the landing party is trespassing, and orders them to leave immediately.

Kirk will not accept Flint's authority, and orders chief engineer Scott on the Enterprise to fire the ship's phasers at their position if they are harmed. McCoy tells Flint about the disease threatening the Enterprise crew and their urgent need for Ryetalyn. Flint displays emotion when he hears McCoy's comparison of the disease to bubonic plague, and describes the agonies suffered by the stricken in Constantinople in the summer of 1334.

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