New financing mechanisms for tropical forest conservation, based on payments for ecosystem services, often involve the development of new business models. Suppliers of ecosystem services may include existing land users (e.g., farmers, foresters, tourism operators) or new business ventures (e.g., carbon accountants and traders, conservation bankers). Developing viable business models for biodiversity conservation is a major challenge, due to: the complexity of biodiversity itself (i.e., genes, species, and ecosystems, many still undocumented); the various linkages between business and biodiversity (which may be an economic input, output, competing resource use, or victim of pollution); insufficient consensus on biodiversity conservation priorities and performance indicators applicable at the enterprise level; weak or missing property rights, liability regimes, and/or incentive measures to penalize biodiversity loss and reward conservation effort; and concerns about potential adverse social impacts. This study presents a synthesis of experience across a range of sectors to develop more sustainable business models for biodiversity conservation, identifies key success factors, and outlines a new approach to building a biodiversity business that combines policy innovation, business development assistance, and financial support.