Fast growing rhizobia that induce nodules on soybean were isolated from China, Vietnam and Papua New Guinea (Balatti, 1994). These organisms were partially characterized by several authors based on physiological and symbiotic characteristics (Sadowsky et al., 1983; CleyetMarel, 1987, Navarro et al., 1996) Several evidences suggest that some of the fast growing isolates might be evolutionary intermediates Therefore, the aim of this project was to fingerprint the genome of fast growing organisms by different PCR methods to analyze the genetic relationship of these organisms.