The countdown is based on the popular iHeartRadio, an Internet radio platform owned by iHeartMedia, Inc. (formerly Clear Channel Broadcasting, Inc.) The show premiered on January 14, 2014 on selected iHeartMedia-owned stations, and is syndicated by Premiere Networks and ARN in Australia.

Internationally, the show airs on Shanghai's KFM 98.1 and the Cayman Islands' X107.1.

On December 26, 2013, iHeartRadio launched a similar "Top Songs of the Year" which was broadcast on Clear Channel-owned CHR stations (such as Z100 New York, KIIS-FM Los Angeles, etc.)

But unlike the U.S. version of the chart, the top 20 songs from both international and Australian acts are aired.

The show broadcasts every Saturday from 2pm to 5pm on all ZM stations nationwide, and is hosted by Cam.