Central Secretariat Service (CSS) is conducted to recruit candidates for Central Secretariat of the Government of India. This service is a legacy of British Raj and has produced a large number of highly efficient civil servants in the country.

Central Secretariat Service is one of the three services of The Central Secretariat, which include Central Secretariat Stenographers' Service (CSSS) and the Central Secretariat Clerical Service (CSCS). CSS is composed of four grades:

• Selection Grade (Deputy Secretary)
• Grade I (Under Secretary)
• Section Officers' grade
• Assistants' grade.

The grades of Selection Grade and Grade I of CSS and as well as the Senior Principal Private Secretary and Principal Private Secretary of CSSS are centralized. The Section Officers Grade and Assistants Grade of the CSS, Steno Grade 'D', 'C', 'A' and 'B' (merged) of CSS and LDS & UDC are decentralized. The grade-wise cadre strength of these services as on 30 June, 2007 was as under:

Grade-wise cadre strength of services