Sustainable development priorities provide the context for Nationally Appropriate Mitigation Actions (NAMAs) by developing countries. While methods exist to assess the sustainable development (SD) co-benefits of Clean Development Mechanism (CDM) projects, no approach has yet been developed to assess the SD impacts of NAMAs. This paper argues for a new integrated approach to asses NAMAs' SD impacts that consists of SD indicators, procedures for stakeholder involvement and safeguards against negative impacts. The argument is based on a review of experience with the CDM’s contribution to SD and a comparison of similarities and differences between NAMAs and CDM. Five elements of a new approach towards assessment of NAMAs SD impacts are suggested based on emerging approaches and methodologies for monitoring, reporting and verification (MRV) of greenhouse gas reductions and SD impacts of NAMAs.