As the World Turns (ATWT) is the second longest-running American television soap opera (the first being Guiding Light), airing each weekday on CBS Daytime.

Set in the fictional town of Oakdale, Illinois, the show debuted on Monday, April 2, 1956 at 1:30pm. Before this show (and The Edge of Night, which premiered on the same day), all soaps were fifteen minutes in length; ATWT was the first half-hour serial.

At first, viewers did not respond to the new half-hour serial, but ratings picked up in its second year, eventually reaching the top spot in the daytime Nielsen Ratings by the fall of 1958. In 1959, the show started a streak of weekly ratings wins that would not be interrupted for over twelve years. In the year-to-date ratings, As the World Turns was the most-watched daytime drama from 1958 until 1978, with ten million viewers tuning in each day. At its height, core actors such as Helen Wagner, Don MacLaughlin, Don Hastings, and Eileen Fulton became nationally known.

The show transitioned from black-and-white to color in the mid-1960s, with the final black-and-white episode airing on February 10 1967. The show expanded from a half-hour in length to one hour starting on December 1 1975. Also in 1975, it transitioned from being televised live to being taped in advance. (ATWT was among the last soaps to make this transition.)

April 2 2006 was the 50th anniversary of the soap opera on CBS. The show aired its 13,000th episode April 23, 2007; the 10,000th episode aired on May 12 1995. As the World Turns is notable for having been taped in New York City for all of its 51 years on television (43 years in Manhattan and eight in Brooklyn).

The daytime serial "Another World" (1964) was conceived as a spinoff of this show. It was submitted to CBS, which decided not to air the new program. After "Another World" was picked up by NBC, CBS refused to allow any major characters from this show to appear on the new one. However, one minor character, Mitchell Dru (Geoffrey Lumb), who had also appeared on the CBS soap opera "Brighter Day, The" (1954), did appear on 'Another World".

Since the cancellation of "Another World" (1964) in 1999, several characters from that show (Jake, Cass, Vicky, Donna and Marley) have made appearances on this one.

One of the first two half-hour soap operas in television. (The other being "Edge of Night, The" (1956), which premiered the same day.)

The first CBS soap opera to expand to one hour (1 December 1975) and the third soap opera to expand to one hour in television history. The first was "Another World" (1964) and the second was "Days of Our Lives" (1965).

Regular color broadcasts began on 20 March 1967.

The episode of 22 November 1963 was broken into by CBS to announce the assassination of President John F. Kennedy. The actors, however, continued performing (as it was done live until 1975), and a complete, uninterrupted copy of this episode still survives.