Lost and Found is the third full-length album by the American heavy metal band Mudvayne. The album is a return to the raw sound heard on the debut album L.D. 50 [MOVLP1691], which was recently released on vinyl for the first time.

Lost and Found is described as a hard rock album with elements of thrash metal. The song "Determined" (originally titled "Fucking Determined") utilizes elements of modern thrash and hardcore punk. The album's first single, "Happy?", featured complex guitar work and the track "Choices" was described by lead vocalist Chad Gray as "the eight-minute opus". The latter the longest Mudvayne song to date.

Drummer Matt McDonough said he believed the music on the album would reflect a refinement of Mudvayne's complex structured hard rock balanced against more melody than any previous album.

The album had major success, being certified Gold by the RIAA shortly after release. It has sold over 1,000,000 copies and is the band's most successful album to date.