A large population of Medicago truncatula insertion lines has been generated using the Tnt1 retrotransposon. More than 21,000 insertion lines have been generated, representing more than 500,000 insertion events. This mutant population is being used by the legume research community to screen for various different mutants using a forward genetics approach. Some of the phenotypes that have been screened using this population include developmentally abnormal phenotypes in leaves, stem, flowers, and roots. In addition to these, mutants with defects in symbiosis with Rhizobium and mycorrhiza, mutants with altered nonhost resistance against Asian Soybean Rust and switch grass rust pathogens, mutants with altered lignin content, mutants with altered cell wall structure, etc. have been identified. Here, we describe the high throughput methodology that is being used to identify these M. truncatula mutants.