A major hurdle in the development of a genetic system for Frankia is the lack of genetic markers. To identify potential genetic markers, 12 strains of Frankia were screened for resistance to antibiotics by the use of a growth inhibition assay. All of the strains demonstrated sensitivity to tested antibiotics. Several strains had distinctive patterns of antibiotic resistance that are potentially useful as genetic markers. Novobiocin was the antibiotic to which the most strains were resistant.Key words: genetics, genetic markers, Frankia, actinorhizal, nitrogen fixation, vesicles.