This publication presents a short introduction to characterization and conservation tools within the context of their practical application in developing countries. It draws on the results of a study on the characterization and conservation of sheep genetic resources in Ethiopia. An overview of approaches to characterization is followed by a discussion of practical considerations in planning and implementation, sampling strategies, the measurement of physical and performance characteristics, biogeographical mapping, production system description and molecular genetic characterization. A further subsection deals with approaches to classifying livestock populations. The section on conservation describes methods for setting conservation priorities as well as conservation methods. Attention is given to the roles of livestock-keeping communities and genetic improvement-based conservation. The conclusion is that characterization work in developing countries needs to focus on approaches that do not rely on time- and resource-intensive activities or on complicated tools. It is also argued that improvements to technical aspects of characterization and conservation need to be complemented by better coordination among the programmes and institutions involved.