It is often believed that this unusual high power was granted as the result of a clerical error by the Canadian Radio-television and Telecommunications Commission (CRTC), but that government organization did not exist at the time.

Unlike other North American superpower FM stations that have lowered their wattage over the years, CKOI-FM actively protected its 307,000-watt signal.

For instance, when Industry Canada advised the station in 2004 that it was out of compliance with updated Code 6 safety regulations (which deal with acceptable levels of radiation), owner Corus Entertainment invested in emission reduction equipment instead of simply reducing power, which would have restricted output to 122,800 watts.

On December 6, 1976, CKVL-FM became CKOI-FM, and the station's format was changed to progressive rock, with a full-time DJ staff.

The fall 1991 Bureau of Broadcast Measurement (BBM) ratings were a defining moment for the station, as it found itself in first place in Montreal with over a million listeners in full coverage.

The station's best-ever results under the old diary system were obtained in the spring 1995 ratings, in which CKOI-FM registered 1,341,300 listeners.

On April 30, 2010, Cogeco announced it would purchase Corus Quebec's radio stations, including CKOI-FM, for $80 million.

[4][5] On December 17, 2010, the CRTC approved the sale of most of Corus's radio stations in Quebec, including CKOI-FM, to Cogeco.

[7][8][9] In 2016, Cogeco applied to the CRTC for permission to move the transmission site to Mount Royal, as space had become available there after the digital TV transition.

Moreover, the move would allow Cogeco to co-locate all its Montreal FM stations, and the superior location would allow CKOI to use lower power to achieve the same reception range.

[10] The station's signal can be heard as far north as Mont-Tremblant, as far east as Drummondville, as far west as the eastern suburbs of Ottawa and down to the Canada-United States border.

They have pranked internationally known personalities such as Jacques Chirac, Britney Spears, Sarah Palin[12] and George W. Bush.

Longtime morning host Normand Brathwaite left CKOI on March 17, 2006, following a conflict with former co-host Jean-René Dufort.