American Top 40

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American Top 40

American Top 40 logo 2021–present.
Other names	AT40
Genre	Music chart show, talk
Running time	4 hrs. (including commercials) 3 hrs. + 15 min. (w/out commercials)
Country of origin	United States
Language(s)	English
Home station	CHR: KIIS-FM (Los Angeles) WHTZ (New York City) HOT AC: KMYI (San Diego) KDMX (Dallas)
Syndicates	Premiere Networks, Radio Express
Hosted by	Ryan Seacrest (2004–present) Casey Kasem (1970–1988, 1998–2004) Shadoe Stevens (1988–1995) See also § Substitute hosts and guest co-hosts
Announcer	Miles Hlivko
Created by	Casey Kasem, Don Bustany, Tom Rounds and Ron Jacobs
Produced by	Easton Allyn & Jennifer Sawalha (Present) Nikki Wine (1970s) Don Bustany (1970s, 1979–1987) Lorre Crimi (1998–2004)
Original release	July 4, 1970 – present (hiatus January 28, 1995 – March 28, 1998)
Website	americantop40.com

American Top 40 (abbreviated to AT40) is an internationally syndicated, independent song countdown radio program created by Casey Kasem, Don Bustany, Tom Rounds, and Ron Jacobs. The program is currently hosted by Ryan Seacrest and presented as an adjunct to his weekday radio program, On Air with Ryan Seacrest.

Originally a production of Watermark Inc. (later a division of ABC Radio known as ABC Watermark, now Cumulus Media Networks), American Top 40 is now distributed by Premiere Networks (a division of iHeartMedia). Nearly 500 radio stations in the United States, and several other territories worldwide air American Top 40, making it one of the most listened-to weekly radio programs in the world. It can also be heard on iHeartRadio, TuneIn, and the official American Top 40 applications on mobile smartphones and tablets as well as on Xbox 360, Xbox One, PlayStation 4 consoles (via iHeartRadio's console app), and the Armed Forces Network. GEICO is the main sponsor for the show.

Co-creator Casey Kasem hosted the original American Top 40 from its inauguration on July 4, 1970, until August 6, 1988. Shadoe Stevens took over the program on August 13, 1988, and hosted until January 28, 1995, when the original program came to an end. Three years later, Kasem teamed up with Premiere's predecessor AMFM Radio Networks to relaunch American Top 40. Kasem, who had spent nine years hosting his own countdown Casey's Top 40 for Westwood One, returned to hosting his creation on March 28, 1998. Seacrest took over American Top 40 on January 10, 2004, following Kasem's retirement from the series.

Currently, American Top 40 with Seacrest airs in two formats, with one distributed to Contemporary Hit Radio (Top 40) stations and the other to Hot Adult Contemporary stations. However, there is no distinction made between the two shows on air. There are also two classic editions of the original American Top 40 distributed every weekend, featuring past Kasem-hosted shows from the 1970s and 1980s.

In its early years, American Top 40 used the Billboard charts to compile the countdown, touting it as "the only source". The program subsequently switched to being based on Radio and Records airplay data upon its late 1990s return,^[1] until R&R was folded into Billboard in 2009. The current source for the American Top 40 charts are unpublished mainstream Top 40 and hot adult contemporary charts compiled by Mediabase.

In October 2021, the show stopped using the AT40 abbreviation and now uses its full name on air. Despite this, some affiliates still use the abbreviation when promoting the show, and Seacrest (as well as guest hosts) occasionally continues to use it throughout the countdown after this change.