The Department of Defence deals with the three Services i.e Army, Air Force, Navy and Coast Guard. It also deals with Inter-Services Organization. It is also responsible for the Defence Budget, establishment matters, defence policy, matters relating to Parliament, defence cooperation with foreign countries, and coordination of all defence related activities. It is headed by Defence Secretary who is assisted by Director General (Acquisition), Additional Secretaries and Joint Secretaries. Defence Secretary is also responsible for coordinating the activities of the other Departments i.e DDP, DESW and DRDO in Ministry of Defence.

Department of Defence consists of following Wings headed by concerned Joint Secretary/Additional Secretary:

Establishment Air PG/Coord Army
Navy PIC Acquisition/CAO Works