Prior to World War II, security cover for Defence Installations was being provided by regular army units, garrison troops, watch and ward wings and chowkidars authorised to various installations. It was in 1947 that a new organisation designated as "Defence Department Constabulary" was raised under Gazette of India Notification No. 1121 dated 26 April 1947. It was re-named as "Ministry of Defence Security Corps (MDSC)" by the Govt of India . The organisation functioned directly under the Ministry of Defence till 16 Aug 1958 when it was re-designated as "Defence Security Corps (DSC)" vide AO 483/58 and placed under the Defence Security Corps Directorate, General Staff Branch, Army Headquarters for command and control. The Directorate was upgraded to Deputy Directorate General of Defence Security Corps on 01 Feb 1985.
The Defence Security is a Corps of the Army and its personnel are subjected to Army Act under Army. The Corps is a Security Force maintained and organised on the Army model. It is responsible for providing security cover to the Defence installations of the three Services and Ministry of Defence civil establishments. Its personnel are armed to such an extent as is compatible with the duties and functions, that they are required to perform, in order to afford a higher degree of protection to Defence Installations. Its personnel are liable to serve throughout India including any area designated as field or operational area by the Government. It is the sixth largest Corps of the Army.