The general nature and evolutionary significance of hybrid zones are discussed. The 21 known or expected zonal interactions between anuran taxa in southern Australia (south of 30°S latitude) are identified; their locations are indicated and, where known, their characteristics are summarised together with the pertinent literature. The interactions between the three call races of Limnodynastes tasmaniensis, and between Ranidella insignifera and R. pseudinsignifera, are described as examples. Reasons for justification of the formal recognition, mapping and delimitation, description and interpretation of the hybrid zones, are advanced. Because of the ongoing fragmentation of the zones through changes in land use, and the accompanying modification of the selective regimes that may influence the structure and location of hybrid zone, it is recommended that the highest priority should be given to increased research on such zonal interactions.