Mates of State are an American indie rock duo, active since 1997. The group is composed of the husband-and-wife team Kori Gardner (vocals, Electone and Hammond B-3 electric organs, Casio synthesizer, and Rhodes electric piano, piano, and occasional guitar) and Jason Hammel (vocals, drum set, glockenspiel, other percussion, and occasional Casio synthesizer).
Gardner and Hammel met in Lawrence, Kansas, while they were involved with other people and other musical projects. Although they exchanged daily e-mails, they didn't get together until three months later when they were both single again, and were inseparable from then on. The main instruments used by the band are drum set and the electric organ. Although they both started out playing the guitar, they found they ended up fooling around with the organ and the drums in their practice space more often than with more traditional instruments. They formed in Lawrence, Kansas in 1997 while both were playing together in a four-piece rock band called Vosotros, in which they both sang and played electric guitar. Shortly thereafter moving to California, Hammel applied to medical school, but opted in 2001 to devote his time to making music and touring with Gardner. They married in 2001.