The Romanian communist secret police, generally known as the Securitate, was officially established under the name of the General Directorate of the People’s Security (Direcţia Generală a Securităţii Poporului – DGSP) through Decree No. 221 of 28 August 1948. The first head of the Securitate was Gheorghe Pintilie (Pantelei Bodnarenco), a former Soviet agent of Ukrainian origin, who had been sent to Romania in 1928 to support the tiny local communist party which had been forced underground in 1924.

Upon its foundation, the Securitate (or the DGSP) was part of the Ministry of Internal Affairs and was composed of ten  directorates, as follows: (1) Directorate I – Domestic Intelligence (Direcţia I Informaţii Interne); (2) Directorate II – Counter-sabotage (Direcţia a II-a Contrasabotaj); (3) Directorate III – Penitentiary Counterintelligence (Direcţia a III-a Contrainformaţii Penitenciare); (4) Directorate IV – Operative (Direcţia a IV-a Operativă); (5) Directorate V – Penal Investigations (Direcţia a V-a Cercetări Penale); (6) Directorate VI – Protection of Ministries (Direcţia a VI-a Protecţia Ministerelor); (7) Directorate VII – Technical (Direcţia a VII-a Tehnică); (8) Directorate VIII – Cadres and Vocational Schools (Direcţia a VIII-a Cadre şi Şcoli Profesionale); (9) Directorate IX – Education, Culture, and Propaganda (Direcţia a IX-a Educaţie, Cultură şi Propagandă); (10) Directorate X – Administration and Accounting (Direcţia a X-a Administraţie şi Contabilitate). The Securitate also had auxiliary services that performed activities such as: censoring of correspondence, surveillance and telephone wiretapping, secretarial tasks, records, encoding, and archiving. Within the territory of communist Romania, there were twelve regional directorates and the Securitate branch of the capital city Bucharest (Securitatea Capitalei). In 1951, the Securitate was reorganised centrally and territorially. It remained part of the Ministry of Internal Affairs, but the official name was changed into the General Directorate of State Security (Direcţia Generală a Securităţii Statului – DGSS) through Decree No. 50 of 30 March 1951. As compared to the previous DGSP, the DGSS had two more directorates: the Directorate for Foreign Intelligence (Direcţia de Informaţii Externe – DIE) and the Directorate for Transportation (Direcţia Transporturi). The territorial structure comprised at that time twenty-eight regional directorates and the General Directorate of the Bucharest Securitate (Direcţia Generală a Securităţii Bucureşti).

During the period 1968–1972, the Securitate functioned independently from the Ministry of Internal Affairs, under the name of the Council for State Security (Consiliul Securităţii Statului), but from 1972, the Securitate became again part of this ministry. From 1972 until the collapse of communism in 1989, the Securitate bore the official name of Department for State Security (Departamentul Securităţii Statului–DSS). In this period, the institution had the following structure: (1) General Directorate for Foreign Intelligence (Direcţia Generală de Informaţii Externe – DGIE), which after 1978 was renamed as the Centre for Foreign Intelligence (Centrul de Informaţii Externe–CIE); (2) Directorate I – Domestic Intelligence (Direcţia I Informaţii Interne); (3) Directorate II – Counterintelligence within the Economic Sectors (Direcţia a II-a Contrainformaţii în Sectoarele Economice); (4) Directorate III – Counterespionage (Direcţia a III-a Contraspionaj); (5) Directorate IV – Military Counterintelligence (Direcţia a IV-a Contrainformaţii Militare); (6) Directorate V –Protection and Guarding (Direcţia a V-a Securitate şi Gardă); (7) Directorate VI –  Penal Investigations (Direcţia a VI-a Cercetări Penale); (8) Command Centre for Operative Technology and Communications (Comandamentul pentru Tehnică Operativă şi Transmisiuni–CTOT), which comprised: (a) (Special Unit “F” for surveillance and investigations (Unitatea Specială “F” de filaj şi investigaţii): (b) Special Unit “P” for research, design and production of operative technology (Unitatea Specială “P” de cercetare, proiectare şi producţie a tehnicii operative); (c) Special Unit “R” for communications and radio counter-intelligence (Unitatea Specială “R” de transmisiuni şi contrainformaţii radio); (d) Special Unit “S” for identification of hidden writing and graphological examinations (Unitatea Specială “S” pentru depistarea scrierilor ascunse şi expertize grafice); (e) Special Unit “T” for installation and management of operative technology (Unitatea Specială “T” de instalare şi exploatare a tehnicii operative); (f) Special Unit for Fighting Against Terrorism (Unitatea Specială de Luptă Antiteroristă – USLA); (9) Centre for Informatics and Documentation (Centrul de Informatică şi Documentare – CID); (10) Service “C” for the transport of secret correspondence (Serviciul “C” pentru transportul corespondenţei secrete); (11) Service “D” for disinformation of espionage centres (Serviciul “D” pentru dezinformarea centrelor de spionaj); (12) Directorate for secretariat and legal issues (Direcţia secretariat-juridică); (13) Service for cadres and education (Serviciul cadre şi învăţămînt). At the level of each of the forty-one counties in communist Romania and of the capital city Bucharest, there was an inspectorate of the Ministry of Internal Affairs, which comprised a Securitate section in charge of the respective administrative unit. The last head of the Securitate was Iulian Vlad, who was nominated in October 1987 and remained in office until 22 December 1989.

The Securitate was dismantled immediately after the 1989 revolutionary regime change in Romania. Thus, the newly established ruling body of the country, the National Salvation Front (Frontul Salvǎrii Naționale – FSN), issued on 30 December 1989 Decree No. 33, whose single article referred to the dismantling of the Department for State Security, that is, the Securitate. After 1989, the Securitate and its crimes became one of the most popular topics of research in Romania, with the former collaborators of this institution being the subject of media articles and public debates. As a result, the Securitate was publicly blamed as being responsible for the brutal repression of opposition which existed in the early days of communism in Romania, and for the successful prevention of any anti-communist movement during the entire communist period. This overall assessment was based rather on personal memories than on archival research, for the documents of the Securitate remained largely inaccessible for fifteen years. While access was restricted, rumours about the destruction of the most compromising files circulated intensely. These rumours were fuelled partly by the discovery of a large number of half-burned documents from the archives of the former Securitate in a forest close to the village of Berevoiești, Argeș county. This event created the public impression that the Securitate was continuing to control the transition from communism to democracy just as much as it was believed to have controlled the communist regime in Romania. Ever since their transfer from the Romanian Intelligence Service (Serviciul Român de Informații–SRI) and from other institutions which hosted them temporarily to the National Council for the Study of the Securitate Archives (Consiliul Național pentru Studierea Arhivelor Securității–CNSAS), the documents of the former Securitate have been frantically accessed by individuals who wanted to see their own file. The case of the Nobel prize winner Herta Müller is perhaps the most internationally famous. Besides, these files have supported the legal process of unmasking Securitate collaborators, with many of the cases uncovered stirring heated debates upon the very definition of the collaborator, as well as on the legal and moral aspects of the act of collaboration. However, public opinion in post-communist Romania continues to consider that many former collaborators are still undisclosed for they are among those who control key political or economic positions in the country. At the same time, it condemns as morally incorrect behaviour any entanglement with the Securitate which implied an act of informing upon another person, and such a vision has been transferred to the young generations born after 1989.