With almost all results in from Saturday's election, the Union of Democratic Forces (UDF) and their coalition partners had 52 per cent of votes, and the Socialist Party, made up of former Communists, had 22 per cent.
The UDF was expected to take 136 or 137 seats in the 240-seat parliament, and the Socialists 57. Third place was won by the Union for National Salvation, which groups ethnic Turks and Bulgarian monarchists and won 7 per cent, giving it 20 seats.
The UDF leader, Ivan Kostov, who is expected to become prime minister, said his four priorities were to implement economic reforms agreed with the International Monetary Fund, tackle organised crime and corruption, open the secret police files on public figures, and prepare Bulgaria for membership of Nato and the European Union. In these tasks he can count on the support of President Petar Stoyanov, elected last November on the UDF ticket.
With reformers in control of the presidency, government and parliament, Bulgaria may have its best chance yet to accelerate the pace of change and catch up with countries such as Hungary and Poland. The Socialists, who have controlled most of Bulgaria's nine governments since the end of one-party rule in 1989, proved to be much more reluctant reformers than their Polish and Hungarian ex-communist colleagues.
Bulgaria's experience closely parallels that of Romania, where former communists retained power after 1989 but were eventually thrown out last year in presidential and parliamentary elections. The UDF achieved its victory after leading a month of street protests in January that forced the Socialists to call early elections and cede power to an interim government. With the Bulgarian economy in crisis, few gave the ex-communists much of a chance in Saturday's vote.
However, the new government's honeymoon with the public is likely to be short-lived, given that the UDF will have no choice but to introduce painful measures to begin with. Under the Socialists, hyper-inflation destroyed Bulgarian living standards, the currency went into free-fall, and the government was virtually bankrupt.
Mr Kostov, an economist, said Bulgaria had a chance of emerging from crisis, but the new government needed to establish firmly reformist credentials. "It is important that we convince the world that a relapse into the past is out of the question," he said.
International lenders have promised a $1.2bn (pounds 750m) loan provided that the government follows a course of strict monetary discipline and privatisation of the still state-dominated economy. The banking sector, which virtually collapsed under the Socialists, must also be rebuilt.