Addala Prabhakar Reddy, after a meeting with Chief Minister N. Kiran Kumar Reddy, announced that he is pulling out.
He told reporters that he decided to withdraw as his defeat could be interpreted as the defeat of the movement for united Andhra Pradesh.
He alleged that YSR Congress party backed out after promising to support him.
Prabhakar Reddy, who had filed his nomination as an Independent candidate, said he had the support of 22 legislators but this was not enough to win.
Earlier, the chief minister advised him to withdraw from the contest.
Prabhakar Reddy and Chaitanya Raju, both belonging to the Congress, had filed nominations as Independents to oppose the central government's decision to bifurcate the state.
While Raju withdrew his nomination Friday, Prabhakar Reddy remained in fray making the elections inevitable for six seats.
Three candidates of Congress, two of Telugu Desam Party (TDP) and one from Telangana Rashtra Samithi (TRS) are in fray.
The Congress has re-nominated T. Subbarami Reddy, K.V.P. Ramachandra Rao and M.A. Khan.
T. Sitarama Lakshmi and G. Mohan Rao are the TDP candidates and if elected they will be entering the house of elders for the first time.
TRS has fielded its general secretary K. Keshava Rao, who is banking on the support of smaller parties and also from some of the legislators of the Congress party.
Out of the six seats which fell vacant, five were held by Congress and one by TDP.