KTDY signed on on September 15, 1966 as KPEL-FM, and was at first a beautiful music simulcast of sister station 1420/KPEL. In the early 1970s, due to Federal Communications Commission (FCC) regulations discouraging full AM/FM simulcasts, KPEL-FM began programming a progressive rock format in the overnight hours, retaining the beautiful music format during the day. Eventually, KPEL-FM changed its calls to KTDY in early 1977, and the progressive format was expanded to broadcast the entire day. In 1979, KTDY began testing a three-hour nightly disco format called "the Electric Disco." The disco experiment only lasted a year before KTDY shifted to become Acadiana's first FM top 40 station as "FM100, Today Radio", beating KSMB by four years. The Disco thing lives on Friday mornings in an all request show called The Polyester Power Hour or PPH for short. After KSMB switched to top 40 on in October 1984, the two stations were engaged in a heated format competition until KTDY shifted to adult contemporary as "Magic 99.9" in 1986.
Since shifting to AC, KTDY has tweaked the format back and forth from mainstream AC to oldies-based Soft AC in the early 1990s to Hot AC in 1998, then back to mainstream AC in 2000.
KTDY at one point aired American Top 40 With Casey Kasem, King Biscuit Flower Hour, Record Report and the Special of the Week with Robert W. Morgan, Scan, Powerline, Earth News, Dr. Demento, Off The Record With Mary Turner, 60 Second LP, and in the early days of the station a strange, daily comedy serial called Kremmin of the Star Corps which turns out was created by well known BBC personality Kenny Everett.
An Ibiquity-licensed station, KTDY began broadcasting HD Radio in August 2007. KTDY was the first commercial station in the Acadiana market to do so, and was the second overall, after KRVS. Currently, KTDY does not multicast. However the DJs have reported that multicast in coming date and how it will be used is unknown at this time.
Its morning show is hosted by C.J. and Debbie Ray. The mid-day show is hosted by Steve Wiley. The afternoon drive time is hosted by JayCee. Who in 2013 was teged by The American Lung Association as Louisiana's Volunteer of the Year. This video from local ABC station KATC TV 3 has more info "http://999ktdy.com/our-own-jaycee-featured-on-katc-spirit-of-acadiana/". It broadcasts the syndicated Delilah starting at 7:00 p.m.