This article first briefly examines the historical basis for the recent movement toward regional environmental integration in Central America. Part II discusses the biological, economic and cultural rationales for a regional, protected-areas system. With this background, Part III reviews the current international law framework for biodiversity conservation. Part IV examines the extent to which existing models of international and regional cooperation incorporate modern scientific principles of conservation biology, such as island biogeography, into their legal framework. Finally, Part V surveys alternative international law approaches for an integrated, regional, protected-areas system to achieve the region's stated goal of preserving an “effective Mesoamerican biological corridor.”