Radio KOST 103.5

KOST (103.5 FM, "KOST 103.5 FM") is a radio station licensed to Los Angeles, California, with an adult contemporary musical format. It is one of three adult contemporary formatted radio station in the Los Angeles/Orange County area, the others being sister KBIG and CBS-owned KTWV, although KOST is softer and plays hits from the mid 1960s to today, while KBIG plays more upbeat hits from the 1980s to today, and KTWV plays softer AC with a hybrid of smooth jazz, making KOST the cross of KBIG and KTWV. The station is one of the top rated radio stations in Los Angeles and one of the top revenue billing radio stations in the United States. According to the radio industry website, RadioStats.Net, KOST's site is the most visited Adult Contemporary radio station website in America. KOST also has translators at 103.9 FM in Thousand Oaks, CA and at 105.5 in Ridgecrest, CA. From 2005-2009, KOST was the only AC station in Los Angeles until KJLL-FM returned to AC having the same old format as when the station was KMLT-FM until 2005.

KOST had a Beautiful Music format until November 1982, when they switched to an all-hit Adult Contemporary format. Over the years, the station has had solid ratings, and there had been little turnover in their air-staff. Bryan Simmons was the first personality for their current format when it began on November 15, 1982 and continues to host afternoons.

The "Mark and Kim" Morning Show had been hosted by Mark Wallengren and Kim Amidon since February 3, 1986. In 2007, KOST owner Clear Channel underwent nationwide budget cuts. KOST was one of the stations affected. As a result, a few KOST personalities were let go. On November 29, 2007, the almost 22-year run of the Mark and Kim morning show ended as Kim Amidon left the station. Mike Sakellarides left on November 30, 2007, after a 25-year run as the first midday host on KOST. Traffic reporter Mike Nolan was let go at the time as well. He has since been rehired. Mark Wallengren is now joined by Kristin Cruz, a radio talent from San Diego. Starting October 2008 the Morning Show became the "Mark and Kristin Show". In 2009, the midday shift was filled by Karen Carson, who had previously been with WLTW in New York.

The station also features Karen Sharp hosting its nightly request and dedication show, "Love Songs on the Coast" Monday through Friday. Christine Martindale serves as weekend host and also hosts "Sunday Journal" every Sunday morning at 6am as part of KOST's Public Affairs programming.

Nationwide budget cuts happened again at Clear Channel in April 2009. This affected KOST longtime weekend hosts, including Cathi Parrish, Brie Tennis and Ted Ziegenbusch. Ziegenbusch was re-hired for fill-in work in early 2010.

The radio station jingles were produced by JAM Creative Productions from 1985 until 2009 and had become an integrated element of KOST's stationality. The station now uses jingles from Reelworld Productions, although some jingles from JAM Creative Productions are still used on the station.

KOST was owned by radio icon Gordon McLendon in the 1960s. It was purchased by Cox Communications in 1973. KOST and sister station KFI were both owned by Cox until 1999. In 1999, KOST and KFI were purchased by AMFM, Inc. In 2000, current owner Clear Channel Communications purchased AMFM, and a result, KOST became a Clear Channel station.