Mezmerize is the fourth studio album by Armenian-American heavy metal band System of a Down. It is the first half of the Mezmerize/Hypnotize double album. It was released on May 17, 2005, six months before Hypnotize, on American Records. The album has sold over 10 million copies worldwide since its release.
Mezmerize was lauded by critics, scoring 85 at Metacritic based on 19 reviews. The album debuted at number one in at least 12 countries, including the US Billboard 200, with 453,000 copies, and has since been certified Platinum by the RIAA. It was chosen as one of Amazon.com's Top 100 Editor's Picks of 2005. The hit single "B.Y.O.B." won a Grammy Award in 2006 for Best Hard Rock Performance.
Despite the time difference between releases, the album actually takes its name from the lyrics in the song "Hypnotize"; Mezmerize and Hypnotize were recorded within the same time frame. The album features guitarist Daron Malakian sharing most of the vocal work with vocalist Serj Tankian, splitting the vocals at least halfway on most of the tracks.