This paper tried to process and go deeper into the complex relationship between the activities of diplomacy and the activities of professional intelligence services. First, the concept of diplomacy is described, some general features of that broad concept, and then the history of diplomatic activity, from the very beginnings to the present day, is briefly covered. Then the role of the Ministry of Foreign Affairs and diplomatic and consular missions, as well as the privileges and immunities enjoyed by diplomats, are described. After dealing with the concept of diplomacy, the second chapter talks about intelligence activities and the way of organizing securityintelligence systems and categories, i.e. ways of collecting information of intelligence significance. After processing the concepts of diplomacy and intelligence, their relationship was considered. It is shown how diplomatic missions can be useful to intelligence services and how services use diplomacy in general, and then the contribution of quality intelligence to the formulation of foreign policy and the implementation of diplomacy is described.