The problem of selecting dogs for animal-assisted intervention work is raised multiple times at conferences and at the work meetings of the International Association of Human-Animal Interaction Organizations (IAHAIO). IAHAIO guidelines contain only general statements about “suitable psyche”, “good physical condition”, and “attitude towards contact with people”. If and how these traits should be checked, it is chosen by the specific organizations. Every organization uses different tests, because there is no specific scientific research on all aspects of the behaviour related to AAI or guidelines produced by experts. From Animals for People Association (Poland), the International Center of Anthrozoology (Norway), and Eötvös Loránd University, Deparment of Ethology (Hungary) in partnership created a standard in the framework of an Erasmus+ application. The listed organizations are among the most recognizable leaders in the field of therapeutic work and the knowledge of the dog behaviour and cognition. We kindly present the PADA (Personality assessment for dogs in AAI) handbook as a result of the cooperation of the organizations. The handbook includes the developed protocol of the PADA mental test, all the background knowledge needed to understand and use the protocol, both scientifically and practically, as well as a suggestion for evaluating the dogs tested. We hope that the following manual will be useful to all interested parties and professionals.