The clean development mechanism (CDM), outlined in Article 12 of the Kyoto Protocol (UNFCCC 1997) is one of the most debated and disputed provisions of the current climate regime. Developing and developed states, business as well as environmental NGOs all seem to be dissatisfied with the mechanism in its current shape, and a reform of the CDM is therefore high on the agenda of the climate negotiations. Even though only states participate in the formal negotiations, non-state actors such as environmental and business NGOs are actively trying to influence the process through issuing position papers, presenting statements and arranging side-events at negotiations. Given that some of their proposals actually influence the negotiations, what factors affect the likelihood of a policy proposal initially presented by a non-state actor to end up in the decision text? Through comparing a range of policy proposals from non-state actors on how to reform the CDM with the decisions taken at the negotiations, the relative success of different policy proposals originating with various non-state actors is assessed. The aim of the paper is to see which non-state actors, and which kinds of policy-proposals, are more successful than others in the negotiations. Two different approaches for explaining differences in success are introduced and tested on the empirical material: a resource-based approach that looks at differences in the resources available to the different non-state actors making the proposals, and a discourse-based approach that looks at how well the different policy proposals fit into the prevailing discourse.