The use of the land around protected areas may pose risks as well as benefit the conservation of biodiversity. Nevertheless, little attention has been given to their management, in the form of clearly established buffer zones (BZ). Moreover, a great deal of confusion exists around their objectives, dimension and location. In this study we review the scientific and technical literature on BZ planning and the related legislation of Argentina, Brazil, Paraguay and Uruguay. Current literature emphasizes the threats to biodiversity from the lands around protected areas, and their role to promote life quality of neighboring communities. On the other hand, neglect the negative impacts of protected areas on the use of land around them, and the potential role of these lands in supplementing or complementing the protection of species and habitats. In the countries which legislation we surveyed, the BZ guidelines are superficial and confusing. The reviewed literature does not present an applied guide for the implementation of BZ. The lack of a comprehensive perception of the relationship between protected areas and their surroundings, clear objectives for buffer zones, and scientific rules for delimitation precludes the integration of these key areas in the effort to conserve biodiversity.