This cost control guide was prepared in response to the request from the OECD/NEA Working Party on Decommissioning and Dismantling (WPDD) – Decommissioning Cost Estimation Group (DCEG) to offer the industry guidance in preparing and implementing cost and schedule controls during decommissioning. The DCEG sent out a survey questionnaire in 2010 soliciting comments from OECD member states on their use of cost controls during decommissioning. While the response was limited, the consensus was to proceed with the preparation of this guide. This guide describes the performance metrics used to determine the value earned based on what was planned to be done, what was actually accomplished and what it actually cost. Variances measured monthly at a minimum indicate where potential problems are arising and raise a flag for the project manager to implement corrective actions for the next reporting period.