It was at all times best known by the acronym UDBA, which is derived from the organization's original name in the Serbo-Croatian language: "Uprava državne bezbednosti" ("Directorate for State Security").

[2] Although it operated with more restraint than secret police agencies in the communist states of Eastern Europe, the UDBA was a feared tool of control.

It is alleged that the UDBA was responsible for the "eliminations"[clarification needed] of thousands of enemies of the state within Yugoslavia and internationally (estimates about 200 assassinations and kidnappings).

Eliminations vary from those during World War II of the Ustaše Croat fascist leader Vjekoslav Luburić in Spain, to Croatian emigrant writer Bruno Bušić and Serbian emigrant writer Dragiša Kašiković, although war criminals have to be distinguished from those assassinated only for dissent or political reasons.

[3] With the breakup of Yugoslavia, the breakaway republics went on to form their own secret police agencies, while the Serbian State Security Directorate kept its UDBA-like name.

After 20 years, in 1966, with the political downfall of its hardliner chief, Aleksandar Ranković, the organization was renamed to the "State Security Service", which (in the Serbian variant of Serbo-Croatian) is Služba državne bezbednosti (Служба државне безбедности), with the corresponding acronym SDB.

After 1946 the UDBA underwent numerous security and intelligence changes due to topical issues at that time, including: fighting gangs; protection of the economy; Cominform/Informbiro; and bureaucratic aspirations.

At home, there were political confrontations both before and after the Brioni Plenum (1966), liberal flareups and massive leftist student demonstrations in Belgrade in 1968, Hrvatsko proljeće (Croatian Spring) or "MASPOK" (mass movement) in Croatia in 1971, a nationalist incursion of the Bugojno group in the Raduša area (1972), and a revival of nationalism in Yugoslav republics.

Some professional cadres, especially those in the "domestic field" (dealing with the "bourgeois right wing", clericalists, and student movements) began leaving the service.

Along with the weakening of the SSDB position, attempts were made by the Yugoslav People's Army Security Service or KOS to strengthen its own strongholds in the different republics and in the individual SDBs.

The attempts failed because they depended upon cadres of other nationalities still employed in the SDBs but who had no access to data bases and had no decision-making power due to their "Yugoslav" orientation.