The government coalition of Chilean socialist President Mr Ricardo Lagos has kept control of the lower House in nationwide congressional election.
But it lost its one-vote majority over the right-wing opposition in the Senate.
Support for the opposition increased substantially in yesterday's election, the first major political test for Mr Lago's 19-month-old government, which is battling a lingering economic crisis.
"In a democracy, who gets more votes is the winner, and we got more votes than the opposition," Mr Lagos told a cheering crowd at the presidential palace. "We are the majority."
With 99 per cent of more than seven million votes counted, the government's centre-left coalition for Democracy had won 64 of the 120 House seats available, compared with 56 seats for the right-wing opposition Alliance for Chile.
The government currently has a 70-50 majority over the opposition; in the Senate, the government coalition and the opposition are split evenly at 24-24 after yesterday's elections.
The 49-seat Senate includes 38 elected lawmakers, nine appointed members and two former presidents who are senators-for-life - one is the suspended former dictator Mr Augusto Pinochet.
With most of the votes counted, the four-party government coalition had 47.9 per cent of the vote, a moderate loss from the 50 per cent it received in the legislative election four years ago.
The opposition had 44 per cent of the vote, a substantial gain from its 30 per cent in 1997. Most of the gains were for the Independent Democratic Union, UDI, a far-right party made up mostly of supporters of Pinochet.
PA