The term ‘active measures’ has already been present in Western discourse on Soviet activities aimed at influencing public opinion abroad since the Cold War, and has recently been brought back to public discourse. However, there is no clear definition for the term. Based on primary sources, this article traces the original KGB definition from the 1970s – agent-operational measures aimed at exerting useful influence on aspects of the political life of a target country which are of interest, its foreign policy, the solution of international problems, misleading the adversary, undermining and weakening his positions, the disruption of his hostile plans, and achievement of other aims – and shows the evolution of the term to ‘support measures’ that are used currently according to Russia’s legislation. The second part of the article is a translation of the chapter on the practical application of ‘active measures’ from the KGB 1989 textbook Political Intelligence from the Territory of the USSR, which has been available to researchers only since December of 2017. In addition to guidance on how such measures should be implemented, the chapter provides an overview of KGB structural units involved in such work, coordination and reporting procedures.