DNA of thirteen Proteus penneri strains derived from four European countries (nine strains from Germany, two strains from United Kingdom, one strain from Turkey, one strain from Hungary) was examined by random amplified polymorphic DNA-PCR (RAPD-PCR) method. RAPD with primer AACGCGCAAC gave different patterns, which suggests a DNA sequence microdiversity within this species. The method provides a fast, economical and reproducible means for typing P. penneri.