In recent years, petroleum reserves and the technical and commercial support underlying them, have become a hot topic of discussion in the investment community and the media. Senior oil company executives, board members and investors alike have become sensitive to the requirements for reserves booking and reporting. Reserves, whether they be Proved, Probable or Possible, are just one part of an oil companies total portfolio that also includes exploration potential and sub-commercial resources. All of these need to be captured and tracked in order to maximize the total portfolio, and ensure accurate and auditable reserves and resource reporting. The SPE/WPC/AAPG reserves and resource classification system provides an excellent framework for capturing and tracking the total resource. This, combined with a clearly defined reserves process linked into, and an integral part of, the engineering and geoscience workflow, will provide assurance to all stakeholders that reserves are under control. Discussion will focus on the need for a reserves system that captures the total resource portfolio, the critical decision points within that system (focal points for corporate governance) and a process that provides quality control and an audit trail to ensure reporting requirements are met.