Considered one of the best odor detectors, dogs go through a rigorous selection and training process. Based on learning theories, modern techniques are used for dog training, respecting individual characteristics, efficiency, and well-being. Since narcotics detection work is perceived as a “play” for the dog, in practice, this promotes a high use rate in the service. The performance of handlers influences the work of the dogs, and well-trained and well-run dogs must work comfortably and accurately. This paper aimed to review the aspects related to the selection, training, and performance of narcotics detection dogs.