The Defence Branch of the Home & Hill Affairs Department liaises with civil and military authorities and handles administrative matters relating to the Rajya Sainik Board and Zila Sainik Boards in West Bengal, in accordance with guidelines of the Kendriya Sainik Board, Ministry of Defence, Government of India.

The Defence Branch deals with welfare-related matters of ex-servicemen and their dependents, including grant-in-aid to World War II veterans and their widows. It processes cases relating to awards for Defence Service personnel from West Bengal, including gallantry and distinguished service awards, and ex-gratia grants to families of Defence personnel killed, missing, or disabled in war actions.

The Branch handles annual maintenance grant matters for paraplegic/quadriplegic ex-servicemen for rehabilitation at recognised centres. It provides administrative assistance for conduct of Defence Forces recruitment rallies and processes arrangements connected with the Rashtriya Indian Military College (RIMC), Dehradun, including entrance examination and scholarships for cadets belonging to West Bengal.

The Branch also deals with Territorial Army matters, grievance redressal of serving Defence personnel, establishment matters and budgetary allocation relating to the Rajya Sainik Board and Zila Sainik Boards, and matters relating to observance of Flag Day, Vijay Diwas, Remembrance Day, heritage sites, war memorials, and disputes concerning Defence land.

The Defence Branch is headed by the Senior Special Secretary / Special Commissioner and is supported by the Deputy Secretary, Section Officer, Head Assistant, and Dealing Assistant, as per the departmental allocation of work.

Guidelines and instructions issued by the Kendriya Sainik Board, Ministry of Defence, Government of India, and relevant Government Orders issued from time to time.