Flagellar motor of bacteria is a rotary apparatus driven by protonmotive force. Flagellar basal body has been believed to be the major part of the motor, because it is the only structure detectable at the proximal end of the flagellum. We developed a new method for the purification of the basal body and analysed the components by SDS-PAGE. The results showed the absence of mot gene products in the structure, suggesting that the functional part of the motor was lost during the purification of the basal body. Three flagellar genes of Salmonella (flaQ, flaN and fla AII. 2) were found to be multifunctional, each giving rise to three distinct mutant phenotypes (Fla-,Mot-and Che-). The phenotypical diversity of these genes implys the participation of the gene products in flagellar assembly, motor rotation and control of the sense of rotation. Genetic analysis of pseudorevertants from Mot- or Che- mutants of the multifunctional genes revealed the interaction among the three genes, suggesting that these gene products make a complex. We present a new image of the motor, where a complex of the multifunctional gene products sits beneath the basal body as the stator of motor and has interaction with motA, B proteins and cheY, Z proteins.