[7] Mariachi El Bronx was recorded in March 2008 at Brandos Paradise in San Gabriel, California with producer and engineer John Avila, who also played charango, sang backing vocals, and mixed the album with the band.

"[16] In March 2009 The Bronx played the South By Southwest festival in Austin, Texas, followed by a tour of the United States ending in June.

[17][18] In an April 2009 interview, Caughthran spoke more about Mariachi El Bronx: The record's been done for a while now, hopefully it's gonna come out in like early or mid summer.

It's all original music, traditional mariachi stuff, and it's the punkest thing in the world for a band like The Bronx to put out a record like that.

[19][20] On the impetus for switching styles for the album, Caughthran remarked that many musicians "kind of blow it by not challenging themselves and not listening to their urges, so to speak.

[23][24] The website Clashmusic.com then offered a free download of "Slave Labor" in August,[25][26] the same month that Wichita Recordings released a single for "Cell Mates" in the United Kingdom.