WKSC-FM (103.5 FM) – branded as 103.5 KISS FM –is a Top 40 (CHR) radio station serving the Chicago area. They are owned by iHeartMedia (formerly Clear Channel Communications until September 2014). The station is known as "103-5 KISS FM" or simply "103-5". WKSC's main competition is WBBM-FM.
WKSC has studios located at the Illinois Center complex on Michigan Avenue in Downtown Chicago, and it broadcasts from a 4.3kw transmitter atop Willis Tower (the former Sears Tower).
As of November 2013, WKSC-FM is the most popular radio station in Chicago with an average of 2.4 million listeners.
WKSC-FM broadcasts in the HD Radio format.
WKSC-FM signed on as WKFM on December 19, 1957, and was owned by Frank Kovas, Jr. The original location of WKFM was at 188 West Randolph, with the transmitter located on the top of the tower. On February 2, 1970, the transmitter fell about 30 stories off the building, but, according to Gary Deeb in the Chicago Sun-Times, no one was injured.