As metapopulation dynamics is thought to play an important role in the conservation of mammals, mainly owing to the fragmentation process, a Population Viability Analysis (PVA) was used to evaluate the role and importance of individual patches to the metapopulation persistence of the long-furred wooly mouse opossum, Micoureus demerarae, a neotropical arboreal marsupial. The metapopulation under study comprises eight small Atlantic Forest patches at Poço das Antas Biological Reserve, southeastern Brazil. The analysis indicates that the local populations may be divided into three groups: (1) in the smallest and most isolated patches, where they are the most endangered, (2) in five circular-shaped and relatively well-connected patches and (3) in the largest patch with the most persistent local population. Knowledge of how specific patches influence metapopulation dynamics is an important tool in guiding management strategies, and dynamics can be affected by factors like patch size and relative position. It seems that for this particular case, probability of metapopulation extinction, mean metapopulation size, heterozygosity and mean growth rate were the most informative measures to evaluate a patch's contribution to metapopulation persistence. Despite all controversies, metapopulation theory, when carefully and properly applied, is a valuable tool in conservation biology.