Aim. In the current situation of Russia's military invasion of Ukraine, national security, territorial integrity and state sovereignty are extremely important for the country's dog services. The benefits of using dogs are much greater than the costs of their maintenance and training. Dogs search for explosive devices, missing soldiers and their remains, detain criminals, and guard military facilities. Different breeds of service dogs are preferred for each special task. Purpose: to study the methods of training service dogs of different breeds of detection service by scent trail and to analyse certain factors affecting the quality of the dog's work. Methods. The research on the topic of the scientific work was conducted in the conditions of the dog training center of the Ministry of Internal Affairs of Ukraine in Vinnytsia region. The following methods were used in the research process: zootechnical, analytical, calculation, biometric. The research materials were used for the study of German Shepherd, Labrador Retriever and Rottweiler dogs, which underwent a general training course and special training for detective work on human scent trails. Results. Service dogs have been used in human life for centuries to protect important facilities and territories, mine clearance, customs service, detention of criminals, search and rescue of people. Training of different breeds of dogs for a particular type of activity, painstaking and careful work of dog handlers, on which the results of dog performance in different conditions of their use depend. Conclusions. The testing of sniffer dogs for human scent detection was carried out in accordance with the existing rules and methods used in the dog training centers of the National Police of Ukraine. The conditions of keeping and feeding the dogs met the standards and recommendations, taking into account the breed, age, live weight, specifics of work and workload, which allowed us to obtain reliable results in the experiments. In the organisation of training and coaching of service dogs, all our studied factors will help dog handlers to use the dog methodically and competently in real circumstances.