Aims: Three molecular typing techniques were examined to determine which method was the most discriminatory in order to perform epidemiological typing of Moraxella catarrhalis.Methods and Results: Twenty-five Mor. catarrhalis isolates obtained from nasopharyngeal aspirates collected from Aboriginal and non-Aboriginal children were subjected to random amplified polymorphic DNA (RAPD) analysis, automated ribotyping and pulsed field gel electrophoresis (PFGE). RAPD analysis determined two Mor. catarrhalis types, automated ribotyping with PstI determined four Mor. catarrhalis ribogroups and PFGE analysis with NotI determined 21 pulse field groups within the 25 isolates examined.Conclusions: Analysis of discrimination index and typeability demonstrated that PFGE is the most discriminatory method for typing Mor. catarrhalis.Significance and Impact of the Study: This study confirms that PFGE is the most appropriate molecular tool for the epidemiological study of Mor. catarrhalis.