Bacterial　diversity　in　sediments　at　UNESCO　World　Heritage　listed　Naracoorte　Caves　was　surveyed　as　part　of　an　investigation　carried　out　in　a　larger　study　on　assessing　microbial　communities　in　caves.　Cave　selection　was　based　on　tourist　accessibility;　Stick　Tomato　and　Alexandra　Cave　(＞　15000　annual　visits)　and　Strawhaven　Cave　was　used　as　control　(no　tourist　access).　Microbial　analysis　showed　that　Bacillus　was　the　most　commonly　detected　microbial　genus　by　culture　dependent　and　independent　survey　of　tourist　accessible　and　inaccessible　areas　of　show　(tourist　accessible)　and　control　caves.　Other　detected　sediment　bacterial　groups　were　assigned　to　the　Firmicutes,　Actinobacteria　and　Proteobacteria.　The　survey　also　showed　differences　in　bacterial　diversity　in　caves　with　human　access　compared　to　the　control　cave　with　the　control　cave　having　unique　microbial　sequences　(Acinetobacter,　Agromyces,　Micrococcus　and　Streptomyces).　The　show　caves　had　higher　bacterial　counts,　different　16S　rDNA　based　DGGE　cluster　patterns　and　principal　component　groupings　compared　to　Strawhaven.　Different　factors　such　as　human　access,　cave　use　and　configurations　could　have　been　responsible　for　the　differences　observed　in　the　bacterial　community　cluster　patterns　(tourist　accessible　and　inaccessible　areas)　of　these　caves.　Cave　sediments　can　therefore　act　as　reservoirs　of　microorganisms.　This　might　have　some　implications　on　cave　conservation　activities　especially　if　these　sediments　harbor　rock　art　degrading　microorganisms　in　caves　with　rock　art.