The election season was turbulent, the EU Observer reported, featuring an attempted bomb attack, a Watergate-like scandal and interference by computer hackers.
Social democrats have governed Sweden for 65 of the last 74 years.
Prime Minister Goran Persson, 57, has delivered the fastest economic growth in six years but the party has reportedly faltered on its promise to cut the high unemployment rate in half. The government also received criticism for its slow response to the Asian tsunami in 2004, which killed 500 Swedes, the Observer said.
The four-party center-right opposition alliance, led by Moderate Party leader Fredrik Reinfeldt, 41, promises tax cuts to help boost employment.
The Alliance for Sweden also includes the Centre Party, the People's Liberal Party and the Christian Democrats.
Last week, Swedish police evacuated an area in the southern city of Malmo after finding a bomb near the People's Liberal Party election booth.