Forests play a crucial role at the interface of the international legal regimes for climate change and biodiversity protection. However, the rules on land use, land-use change and forestry developed under the Kyoto Protocol have only provided limited incentives to protect biodiversity. A new opportunity to exploit potential synergies between the climate and biodiversity regimes is provided by the ongoing negotiations on reduced emissions from deforestation and forest degradation (REDD), yet the biodiversity impacts of a REDD mechanism will crucially depend on its design. Against that background, this article suggests and examines various options to integrate biodiversity considerations in REDD design. It shows that while the explicit incorporation of biodiversity considerations is possible, doing so will force negotiators to make inevitable tradeoffs. The first tradeoff is between pursuing a legally binding agreement and strong references to biodiversity in a future agreement, whereas the second tradeoff is between the strength of such references and the need to secure countries' participation in a future REDD mechanism. Nevertheless, the article concludes that such tradeoffs need not necessarily lead to the exclusion of biodiversity concerns under a future climate regime.