Owned and operated by Corus Entertainment, it broadcasts on 96.9 MHz from the roof of the CIBC Tower in Downtown Montreal with an effective radiated power of 307,000 watts (class C1) using an omnidirectional antenna. It is one of the few Montreal FM stations to not use the standard Mount Royal tower, and it is one of North America's most powerful FM stations.
CKVL-FM, as the station was originally known, was founded by Jack Tietolman and probably went on the air at some point between 1947 and 1957. Sources disagree on the date, and at least seven different years (including three post-1957 ones) are known to have been reported as the station's first air date. The confusion is increased by the fact that there is no known report suggesting that the station went silent for any noticeable period of time after getting on the air, despite this phenomenon being relatively common among 1950s FM stations. In any case, the Canadian Communication Foundation, which claims the station's first air date was in 1947, does report that CKVL-FM was confirmed as being on the air in 1957.
By 1962, CKVL-FM increased its power from 10,000 watts to 307,000 watts omnidirectional from the rooftop of the CIBC Tower in downtown Montreal. It is often believed that this high power was the result of a clerical error by the CRTC, but that organization did not exist at the time as radio was still regulated by the CRTC's predecessor, the Board of Broadcast Governors, and regulations limiting effective radiated power to 100,000 watts on FM, which came into force that same year, do not apply to stations which had already got approval for a higher power.
The simulcast of CKVL ended in 1970, as CKVL-FM launched an automated oldies format.
On December 6, 1976, CKVL-FM became CKOI-FM, and the station's format was changed to progressive rock. It evolved into a largely New Wave based format in 1979 and adopted a rock-leaning contemporary hit radio format in 1980. Humoristic programming started to take an increasing place on the station by 1991; the station would became known for pranks that caught internationally-known personalities, the latest being perpetrated against French President Jacques Chirac by Les justiciers masqués ("The Masked Avengers", a duo composed of Marc-Antoine Audette and Sebastien Trudel), who tricked Chirac into talking to them by posing as officials, and then as Conservative Party of Canada leader Stephen Harper (after the 2006 election but before Harper was sworn in as Prime Minister of Canada).
The Fall 1991 Bureau of Broadcast Measurement ratings were a defining moment for the station, as it found itself in first place with over a million listeners in full coverage. It was the first time ever in Montreal that any FM station obtained the first place in the Fall ratings, which are by far the most important for the radio industry as they are used to determine prices charged for publicity. CKOI-FM would get over a million listeners in 32 consecutive books (excluding Summer ratings starting in 2001 which were only done for the central area of the market), from Fall 1991 to Fall 2002 inclusively. (The station had already managed to get a million listeners on a few occasions during Summer ratings before 1991.) The station's best-ever results were obtained in the Spring 1995 ratings, in which CKOI-FM got 1,341,300 listeners; by comparison, CKAC, which was the station's closest competitor, got only 775,500 listeners.
CKOI-FM, along with sister station CKVL, was sold in 1992 by its founder Jack Tietolman to Metromedia CMR, a company owned by Pierre Arcand and Pierre Béland. Both stations would be sold again in 2001, this time to Corus Entertainment.
On January 1, 2002, the station's city of licence became Montreal (it had always officially been Verdun until then), as a result of forced municipal mergers which made Verdun a Montreal borough.
Unlike other North American superpower FM stations which have lowered their power since the 1990s, CKOI-FM does cherishes its signal; as a result, when Industry Canada advised the station in 2004 that it was not compliant with updated Code 6 safety regulations (which deal with acceptable levels of radiation), owner Corus Entertainment invested to make the transmitter compliant, instead of taking the "easy way" out, which would have been in this specific case to reduce power to "only" 122,800 watts.
The station's studios were moved for the first time ever in July 2006, after decades at 211 Gordon Avenue in Verdun; the new studios are located at Place Bonaventure.