The objective of this manual is to provide a working document for port State authorities to use in the implementation of the IOTC Port State Measures Resolution (PSMR), which entered into force on 1 March 2011 and was amended in 2016 to include a provision on the electronic port State measures application (e-PSM). The content is divided into three chapters. The first chapter describes the functions and operations of IOTC and the Indian Ocean tuna fishery, and summarises the development of port State measures by the international community and the development by IOTC Contracting Parties and Cooperating Non-Contracting Parties (CPCs) of conservation and management measures that both reflect and complement the internationally agreed measures. The second chapter addresses operational and technical matters, key elements for the training of managers and inspectors, to provide them with the knowledge to implement the port State measures practically and effectively. The third chapter provides guides to and checklists for standard operating procedures to implement the measures for vessels from the main fishing sectors likely to be encountered in the Indian Ocean region. This manual should be viewed as a living document that can be revised and improved by all parties as experience is expanded in the implementation of the IOTC PSMR.