The occurrence of Leadbeater's possum, Gym- nobelideus leadbeateri (McCoy) is restricted to a narrow set of climatic conditions which are confined to the Central Highlands of Victoria. This area encompasses the entire known range of the species. Bioclimatic analyses using the computer program BIOCLIM allowed the prediction and definition of the potential limits of the distribution of G. leadbeateri. This was used as a basis for selecting sites for surveys for G. leadbeateri outside the Victorian Central Highlands. G. leadbeateri was not detected in field surveys of these sites. The bioclimatic profile of G. leadbeateri was closely related to the bioclimatic profiles of several species of trees, including Eucalyptus regnans, Acacia obliquinervia and Acacia frigiscens. However, none of the plants that were examined in the study could be used as an indicator of the presence of G. leadbeateri. On the basis of its bioclimatic profile, the distribution of G. leadbeateri is likely to undergo a considerable contrac- tion as a result of climatic changes associated with the 'greenhouse effect'. The importance of this result and other findings from the study are discussed in terms of the value of BIOCLIM and bioclimatic analyses in wildlife conservation.