Mongolia's primary law enforcement organisation, an agency of the Ministry of Justice and Home Affairs headquartered in Ulaanbaatar. Its founding day is 19 July 1921, when the Sixth Session of the Little Khural decreed the establishment of the Preventive Militia with a modern police mandate; in 1965 the police were made a separate institution from the Prosecutor's Office, and after the 1990s transition the force was re-established as the National Police Agency (National Police Agency, police.gov.mn; Devex organisation profile).

Under the Law on Police Service, the head of the central police organisation is appointed and discharged by the Government on the proposal of the cabinet member in charge of internal affairs, must have served at least 20 years in the police with a higher legal education and no prior political office, and manages police activity nationwide with a first deputy chief and two deputy chiefs (Law on Police Service, Articles 20.1-20.3, legalinfo.mn). Its central units include the Criminal Police Directorate, the Criminal Investigation Directorate, the Counter Narcotics Department, the Ecological Police Directorate, the Transportation Police Directorate and the Interpol National Central Bureau, with police departments and divisions in all 21 aimags and in Ulaanbaatar (National Police Agency organisational structure, police.gov.mn).