The profile of streptomycin-, erythromycin-, bryamycin- (thiostrepton), spectinomycin and lincomycin-resistance transforming activity has been compared with the distribution of the ribosomal RNA genes on methylated albumin kieselguhr columns. We have found that the str, ery, spc and lin genes showed different methylated albumin kieselguhr profiles from the rRNA genes and are not linked at the molecular weight of DNA employed in these studies (4.5 × 10 6 single-strand molecular weight). Thus, these genes are different from rRNA cistrons, and the r-proteins which they presumably code for are not formed by the translation of rRNA templates. Only the bry gene exhibited a methylated albumin kieselguhr column distribution similar to that of the rRNA genes. However, mercuric cesium sulfate isopycnic centrifugation of rRNA- bry DNA hybrids failed to demonstrate linkage between rRNA genes and the bry marker, at this level.