"Most likely the forthcoming assembly election will be the last election for me," Siddaramaiah told reporters at Raichur in north Karnataka.
However, he maintained that he would remain active in politics, but not contest assembly polls.
Earlier during the 2013 assembly polls, Siddaramaiah had said it was his last election.
Conceding that he had during the 2013 polls stated it would be his last election, the Chief Minister said he was contesting to stop BJP from getting back to power.
"Looking at elections and the political system, I had felt it is enough. But looking at communal politics by the BJP, I felt I should stand in election. Also, the high command said that I should contest," he said.
"I have the responsibility to see to that BJP does not come back to power, so I'm contesting," he added.
The Congress has announced Siddaramaiah would be the party's face during the 2018 Assembly polls.
He said he would contest the Chamundeshwari constituency in Mysuru district and added there are 20 constituencies other than Varuna from where he could win.
"Chamundeshwari is the constituency that gave me political strength and a rebirth, so I felt I should end from there," he said.
Making his debut in the Assembly in 1983, Siddaramaiah got elected from Chamundeshwari on a Lok Dal Party ticket. He has won from the constituency five times and seen defeat twice.
Siddaramaiah represents Varuna in Mysuru after it became a constituency in 2008 following delimitation.
Speculations are rife that the chief minister is keen on fielding his son Yatindra from Varuna.