"In the Year 2525 (Exordium and Terminus)" is a hit song from 1969 by the Lincoln, Nebraska duo Zager and Evans which reached number one on the Billboard Hot 100 for the six weeks commencing July 12. The song was written by Rick Evans in 1964 and originally released on a small regional record label (Truth Records) in 1968. A year later, an Odessa, Texas radio station popularized the disc, which RCA Records quickly picked up for nationwide distribution.

"In the Year 2525 (Exordium and Terminus)" opens with the words "In the year 2525, If man is still alive, If woman can survive, They may find...". Subsequent verses pick up the story at 1010-year intervals from 2525 to 6565. Disturbing predictions are given for each selected year. In the year 3535, for example, all of a person's actions, words and thoughts will be preprogrammed into a daily pill. Then the pattern as well as the music changes, going up a half step in the key of the song, after two stanzas, first from A flat minor, to A minor, and, then, finally, to B flat minor, and verses for the years 7510, 8510 and 9595 follow.

The song has no chorus. Amid ominous-sounding orchestral music, the final dated chronological verse is, In the year 9595, I'm kinda wonderin' if Man is gonna be alive. He's taken everything this old Earth can give, and he ain't put back nothing, whoa-whoa..., The summary verse concludes: Now it's been 10,000 years, Man has cried a billion tears, For what, he never knew. Now man's reign is through. But through eternal night, The twinkling of starlight. So very far away, Maybe it's only yesterday., before the song effectively "starts over" with the first verse again and then fades out, leaving open the possibility that "we went through this before," and life is now at the start of another cycle.

The overriding theme, of a world doomed by its passive acquiescence to and overdependence on its own overdone technologies, struck a resonant chord in millions of people around the world in the late 1960s.

The song describes a nightmarish vision of the future as man's technological inventions gradually dehumanize him. It includes a colloquial reference to the Second Coming ( In the year 7510, if God's a-coming, He ought to make it by then.), which echoed the zeitgeist of the Jesus Movement. The song also references examples of technologies that were not fully developed but were known to the public in 1969, such as robots, as well as future technology that would come into existence long before their prediction in the song, the science of test tube babies and genetic selection by parents of their future children. Such a concept had been explored in a few science fiction novels but had not yet, for the most part, been mentioned in the mainstream media until "In The Year 2525" was released in 1969.

In one of the daily newscast to the crew of Apollo 11 capsule communicator Ronald Evans told the returning crew that "In the Year 2525" was currently number one in the billboard charts after also informing the crew about the large number of Moon based songs that had just been written following the successful Moon Landing.

It is unusual for a recording artist to have a number one hit and then never have another chart single for the rest of their career. "In the Year 2525" actually gave Zager and Evans this status twice: they remain the only act to do this in both the U.S. andUK singles charts. The duo also recorded and released the song in Italian under the title of "Nell'Anno Due Mila Trenta Tre" ("In The Year 2033"). Their follow up single on RCA-Victor, "Mr. Turnkey" (a song about a rapist who nails his own wrist to the wall as punishment for his crime), failed to hit the main music charts on either side of the Atlantic (although it did manage to make the Bubbling Under Hot 100 chart, peaking at #106).

The song has been covered many times. A notable version is sung by the italo-french pop icon Dalida, another one by the UK new romantic group Visage; another version was used as the theme song for the short-lived science fiction series Cleopatra 2525. It is also featured in both parts of the two-part second season finale of Millenniumwhere a man-made virus is threatening to wipe out humanity. The Slovenian industrial group Laibach edited the lyrics in their cover version to make it appropriate for 1994's album. There was also a dance cover of this song by The Act featuring Clinton III in 1993. More recently, it was covered by the gothic rock band Fields of the Nephilim, by the electronic body music band Project Pitchfork (album Dhyani), 1991, by the German electronic band Strauss & Roggenbuck, and most recently by Ian Brown on his 2009 album "My Way".

In the 1992 movie Alien 3, a prisoner is heard singing a line or two of the song while scraping the inside of a ventilator shaft, shortly before he is attacked by a juvenile Xenomorph and subsequently diced by a large ventilation fan. The movie takes place a few hundred years after the 20th century.

The song appeared on the list of songs deemed inappropriate by Clear Channel following the September 11, 2001 attacks.

The song still receives regular airplay on many radio stations. It was often featured as bumper music on Coast to Coast AMwith Art Bell (before Bell retired). "In The Year 2525" was one of the 10 biggest singles of the 1960s in the United States, although it didn't neatly fit into any of the main categories of rock music. Upon release by RCA in 1969, it quickly became a multi-million-seller.

According to Jimmy Guterman and Owen O'Donnell, authors of The Worst Rock and Roll Records of All Time(1991), who place the song at number six on their list of the 50 worst rock-and-roll singles, "science fiction and rock and roll don't mix any better than Zsa Zsa Gabor and reality". Others differ, calling the one-hit wonder "prophetic" .

The White Stripes refer to "the year 2525" in the song "You're Pretty Good Looking (For a Girl)" on their album (2000).

The song was prominently featured in the 2009 comedy Gentlemen Broncos starring Michael Angarano, Sam Rockwell and Jermaine Clement.