The SDP was founded on 20 May 1959 through the merger of the Democratic Party and the Socialist Unity Faction.

[citation needed] The founding convention of the party took place in Tenali.

However, the different groups that had merged to form SDP continued to exist as distinct tendencies.

Latchanna and Chenna Reddy became leaders of the Andhra Pradesh unit of the Swatantra Party.

The Speaker of the Andhra Pradesh Legislative Assembly declared the SDP dissolved on 10 December 1959.