The station began broadcasting in 1974 as KVDB-FM, with "VDB" being a subtle reference to its owner, Russell Vande Brake. KVDB-FM was the sister station to KVDB (1090 AM, now KSOU), which broadcast from the same studio. During the day, they had separate programming, but in the evening, an easy listening format was simulcast over both stations.
On August 1, 1989, the station changed its call sign to KTSB; on April 1, 1996, it changed to the current KSOU-FM.[3]
