Old Cadets Association of Sylhet (OCAS) was established in Dhaka on 6th august 1982.

Principal of Sylhet Cadet College at that time was the the first President of OCAS. The first Vice President was Md Afaq Ahmad (01/186) and to lead the organization further, Farooque Mohammad (01/02) was selected as first General Secretary (GS).

The first Constitution of OCAS was made in 1982. Later in 2002, 2015 and 2019, some amendments were done. The final constitution approved in 2019 at the Annual General Meeting, which submitted and approved by RJSC.

The first reunion was held in 1990 at Sylhet Cadet College. The President and GS during the first reunion were Mirza Ashab Baig (01/198) and Md Abdun Naser Khan (04/35) respectively.

Old Cadets Association of Sylhet has been finally registered on 29th December 2020 under the Act No. XXI of 1860 (an Act for registration of literary, scientific and charitable societies) with the office of the Registrar of Joint Stock Companies & Firms, Bangladesh.