Many, but not all, Azospirillum species are genetically tractable bacteria. Replicative and suicide vectors are available for allelic exchange, in trans gene expression, functional complementation, and reporter gene analyses. Because Azospirillum species are closely related to Rhizobiaceae, tools used in Rhizobia have been typically employed for the genetic manipulation of Azospirillum species. Insertional and deletion allelic exchanges have been optimized for Azospirillum. Azospirillum is not competent, and there is no phage transduction available for genome manipulation yet. The vast majority of genetic manipulation over the last several decades has occurred using conjugation. Generally, plasmids are constructed in donor E. coli strains and then conjugated into the acceptor Azospirillum strain. While this molecular kit can be further expanded, it is currently sufficient to address the molecular mechanisms underlying Azospirillum physiology and their beneficial association with the roots of many plants.