On 27 July 2003, the oil tanker Tasman Spirit ran aground spilling a portion of its 67,000-tonne cargo of Iranian Light Crude Oil into Karachi Harbour, in Karachi, Pakistan. The loss of product resulted in environmental damage with heavy oiling of the shoreline in Karachi Harbour and surrounding areas. Recognizing the need for international guidance to assist nations in assessing damage to natural resources following major oil spills in the aftermath of this incident, the United Nations Environment Programme (UNEP), soon thereafter, initiated the development of a manual on natural resource damage assessment and restoration following major oil spills. Given IMO's specialised expertise on preparedness for and response to accidental marine pollution issues and the long history of collaboration between IMO and UNEP, the two organisations agreed to the development of the Manual as a joint publication. With a view to providing operational guidance, the IMO/UNEP Guidance manual on the assessment and restoration of environmental damage following marine oil spills has been developed through the OPRC-HNS Technical Group of the Marine Environment Protection Committee of IMO, in full collaboration and partnership with the United Nations Environment Programme. The objective of the Manual is to provide guidance on strategies that may be used to assess the damage and subsequent recovery of the environment resulting from marine pollution incidents. Available techniques are considered together with criteria to help judge the feasibility of such measures to bring about successful recovery of those environments. The Manual emphasizes the importance of pre-spill planning and provides an overview of assessment techniques and restoration measures in various ecosystems. It also provides guidance on opportunities for compensation through the international oil compensation schemes. Practical examples of natural resource assessment and restoration are provided through a series of case studies.