This manual is designed to be used by the trainee at Special Program for Research and Training in Tropical Diseases and Good Laboratory Practice training workshops. It contains an introduction which highlights the history of the OECD principles of GLP, and the fundamental points. Included is training on the resources required (personnel and facilities); preparation of the protocol and standard operating procedures (SOPs); characterization of the test item (its storage, use, quality control, test system); documentation (reporting, deviations from the protocol, indexing, archiving, retrieval); and quality assurance (validity of results must be ensured through all phases of a study). The material is presented in a clear, lively and informative way. Also included are several practical and interesting workshops on how to prepare, review and improve protocols and standard operating procedures, based on actual case studies. Finally there is a self-assessment questionnaire "so the trainee can recognize how much he/she has learned and what issues need clarification, if any.