Abstract This Manual is part of the teaching material prepared especially for the use of training workshops dealing with techniques for collecting information, country by country, on all measures pertaining to trade in services in the countries of the western hemisphere. The Manual is designed to be updated as the training workshops progress, to take account of the suggestions and improvements that come out of these. The Manual includes basic background material on quantitative aspects of services trade in the world and in the countries of the hemisphere (Section I);. Next, information is given about the World Trade Organization (WTO); (Section II); along with more detailed information on the rules and results arrived at by the General Agreement on Trade in Services (GATS); of WTO (Section III);. This section emphasizes the basic principles on which progressive liberalization of services rests, and which will be used to organize and classify the information collected. Section IV explains the logic used to structure services negotiations. Since measures pertaining to services are at the heart of the negotiating process, the objective of this Section is to emphasize how important it is for negotiators to have the fullest possible information about measures affecting trade in services in their own countries and about the reasons for these measures in terms of national policy objectives. Section V stresses the importance of modes of supply in services trade, while Section VI identifies some practical steps for organizing the tracking of measures nationally. The rest of the Manual contains practical examples to assist in completing the Questionnaire designed for collecting information on measures, and a typology of the measures most commonly used by countries to regulate their services. The Manual contains an Annex that profiles the main service industries, including an abundance of information about their trading activities and relevant details about their international operations. The purpose of this section is to assist in the analysis that the countries will have to carry out when they come to assess the trade implications of their services commitments.