CIBX traces its history to the first radio station in New Brunswick, CFNB (the call letters naturally stood for Fredericton, New Brunswick). The station went on the air under the experimental callsign of 10AD and at 1210 kHz in 1923. It was granted a full license as CFNB in 1926. CFNB then moved to 1030 in 1933, and finally to 550 in 1934. The station was affiliated to the CBC's Trans-Canada Network. In 1959 the station increased its power to 50,000 watts, giving it full-time coverage over most of the Maritime Provinces. The CBC affiliation as dropped in 1964 when the network started its own station in Fredericton, CBZ. The station played an adult contemporary format before switching to oldies in the early 1990s.
In 1996, CFNB's parent company, Radio Atlantic was granted permission to move its signal to 106.9 FM and to eliminate its AM transmitter. The callsign changed in the process, and after a brief simulcast period, CFNB signed off on June 11 of that year. The new station, CIBX, played soft rock. The former CFNB callsign now belongs to a radio station out in D'Arcy, British Columbia, known as CFNB-FM. Over time, the station evolved towards hot adult contemporary.
Between 2000 and 2005, CIBX used the on-air "EZ Rock" branding along with other stations in Canada (while using "Capital FM" as a secondary name), though they have returned to using only the "Capital FM" name.
As of July 18, 2012, CIBX has officially flipped to Top 40.
CIBX and seven other radio stations in the Atlantic provinces are currently owned by Bell Media.