Abstract: Different Salmonella species (159 strains) were isolated from human and non-human sources were exposed to eighteen different antibiotics. 48 strains showed resistance to one or more antibiotics. Resistant strains were examined for their R- plasmids contents by glass fines, boiling miniprep and agarose electrophoresis procedures. All but three of the tested strains from chicken contained a plasmid with similar molecular weight (m.w.) even though the strains were resistant to different antibiotics. The remaining three strains contained an additional plasmid with a different electrophoretic migration pattern. Many of the plasmids when digested with endonucleases were found to have similar fragments. Out of four plasmids extracted from Salmonella strains isolated from sheep, three contained one type of a plasmid with similar m.w. and fragmentation. Broad diversity was noted in plasmids extracted from Salmonella strains isolated from humans. Endonuclease digestion of plasmids revealed that some plasmids have a common fingerprint pattern.