Mapping the ‘data sources’ on animal diseases, in each European Union (EU) Member State, is one of the activities of EFSA's SIGMA1 project. The aim of this activity is to identify the central competent authorities responsible for managing the data on animal diseases and animal populations in each Member State. Initially EFSA is focusing on three diseases (on which Animal Health and Plant Health Unit is currently working): African swine fever, avian influenza and lumpy skin disease; and on the corresponding affected animal populations: swine, poultry and bovines, respectively. This technical report describes the details of the methodology implemented by EFSA for the mapping of the data sources in each EU Member State. In order to collect all the information needed, EFSA launched an online questionnaire, through the EUSurvey application, to the 28 EU Member States. The information received was assessed and validated in close collaboration with each country. The results of this activity will be published separately per Member State as a technical report where the ‘Country Card’ for each one will be included. This ‘Country Card’ summarises the information related to the central competent authorities responsible for the data on animal diseases (data on outbreaks, surveillance activities and laboratory results) and on animal populations (bovines, swine, poultry).