KCWI signed on the air January 20, 2001, as a WB network affiliate under the call sign KPWB-TV. (The KPWB call letters were originally used on channel 31 in Sacramento from 1995-1998 as a WB affiliate and a Pappas owned station, later becoming UPN O&O KMAX-TV, which also joined The CW.) KPWB carried the full WB and Kids WB lineups until the WB and UPN merged into the new CW Network in September 2006.
Syndicated programs on KCWI include The Tyra Banks Show and reruns of Friends, King of Queens, That '70s Show, and Will & Grace. KCWI also carries St. Louis Cardinals games on Sundays during baseball season and Kansas City Chiefs games during the NFL's pre-season.
On January 24, 2006, The WB and UPN networks announced that they would cease broadcasting and merge to create a new network. The new combined network would be called The CW, the letters representing the first initial of its corporate parents: CBS (the parent company of UPN) and the Warner Bros. unit of Time Warner.
On February 22, 2006, News Corporation announced that they would start up another new network called MyNetworkTV. The new network, which would be sister to FOX, would be operated by FOX Television Stations, Inc. and its syndication division Twentieth Television. MyNetworkTV was created in order to give UPN and WB stations, not mentioned as becoming CW affiliates, another option besides becoming independent. It was also created to compete against The CW.
It seemed very likely that KPWB would become The CW's affiliate in Des Moines, as WHO-TV had a secondary affiliation with UPN. On March 16, 2006, it was confirmed that KPWB would become the CW affiliate in Des Moines. A few months later, MyNetworkTV announced that it would affiliate with a new station also owned by Pappas, KDMI, which began broadcasting that network on September 5, 2006. On September 18, 2006, the same day The CW launched, KPWB changed its call letters to KCWI to reflect its new affiliation.
Due to this abnormality, KCWI's digital signal is carried as a subchannel of KDMI.