- 1976-77 lt. col. Oldřich Mézl
- 1977-83 maj. Josef Nevečeřal
- 1983-88 lt. col. Josef Beneš
- 1974-77 deputy chief lt. col. Jiří Krumphanzl
- 1983-88 deputy chief lt. col. Václav Šíma "Amis"
The Section worked on the issues of ideologial diversion and emigration. It was also in charge of “channels” through which the opposition communicated with the free world. The third Department focused on Ukrainian nationalists and collaborated very closely with the KGB. The most important actions led by Department 4 were files on Jiří Pelikán and Pavel Tigrid. Action Delta against Jiřina Šiklová and others from spring 1981 is also worth mentioning, leading to one of the uncovered roads for smuggling literature. The Section participated in several propaganda films broadcast by Czechoslovak television (“Trees giving no shade”, “A deal with trust”, “EM4 is coming”, etc.)
- Department 1 – Zionism, jewish nationalism, pro-Zionist intelligentsia in science, pro-Zionist youth and world Zionist centres,
- Department 2 – Organisation of Ukrainian nationalists (OUN), Narodno-trudovoy soyuz (NTS), centres of so-called Eastern emigration, Anti-bolshevik bloc of countries (ABN), Radio Liberty, RFE
- Department 3 – former representatives of reactionary political parties, counter-revolutionary and extreme forbidden organisations, former punished agents of enemy foreign intelligence, protection of the parties of the National front, Greek emigration, Trockyism and Maoism,
- Department 4 – illegal press materials and anonymous threat letters, terror, illegal arms, monitoring of records and processing of enemy persons.