Given the greater vulnerability of developing countries to climate change, their paramount interest is to establish effective mitigation policies including the land use and forestry sectors as part of the post-2012 Climate Agreement. In this context, an accounting system for land use, land use change and forestry acceptable to non-Annex I Parties can arise only if critical elements in current accounting rules are removed and a solution to data uncertainties is found. Indeed, current accounting rules oppose the fundamental principles outlined in the both Convention on climate change and in the Kyoto protocol. They require accounting of only a portion of land-use activities and exclude forest management, give special provisions to exclude some net emissions from accounting, do not require the use of a reference level in quantifying net emissions and risk remunerating business as usual mitigation actions. Encouragingly, the current negotiation text contains options which, if adopted, would define an accounting system capable of responding to developing countries’ expectations. These options include the establishment of a national reference level suited to country-specific circumstances and other measures to ensure that only truly additional mitigation actions are remunerated and that all anthropogenic net emissions on managed lands are included. Finally, the opportunity of applying the principle of conservativeness in the future accounting routine is discussed, as a straightforward and effective instrument to correct uncertain estimates and therefore to reduce the risks of assigning an incorrect amount of credits and debits in this complex sector.