Panic! At The Disco was formed in when Brandon Urie asked for a guitar for Christmas. Not to be left out, neighbor Spencer Smith, asked for drums. Later school friends Brent Wilson, bass, and Ryan Ross, guitar, joined the band. The band went to high school in a suburb of Las Vegas, Nevada, covering Blink 182 songs.

Their music would be classified as pop/rock, including theatrical touches, techno beats and perceptive lyrics in their songs and music videos. They posted demos on the internet and quickly got the attention of Decaydance, a record label Fall Out Boy bassist, Pete Wentz, made under the Fueled By Ramen label. P!ATD was soon the first band signed by Decaydance.

In September of 2005, their first CD, A Fever You Can't Sweat Out, hit music stores everywhere. They quickly went on the Nintendo Fusion Tour performing with bands such as Fall Out Boy, Motion City Soundtrack, Boys Night Out, and the Starting Line. Their single "I Write Sins Not Tragedies" came out on radio airwaves and made it to TRL’s Top 40. They soon went on tour with Academy Is..., Acceptance, and Hellogoodbye.