DBS Staff Union was formed in 1997 as a House Union with membership of 1350. In July 1998, POSB was acquired by DBS Bank. The POSB Employees Union with 1400 membership was dissolved and merged with DBS Staff Union as one Union with total membership of 2750. Officials from both Unions together with Human Resource partners were critical in harmonizing the terms and conditions for its members during the acquisition. It was completed in December 1998.

DBS Staff Union held its first Triennial Delegate Conference (TDC) in 2000. Subsequently, in 2003, 2006 and 2011 where the Quadrennial Delegates was held.

With a team of dedicated and committed Exco, the team was critical in promoting and emphasizing the importance of members' welfare and the necessity for peaceful resolutions in all industrial relations matters. At the same time, a positive mind set was adopted to be pro-member and pro- business.