Polling stations opened at 7 a.m. local time (0500 GMT) for more than 18.3 million eligible voters in the country of 21.5 million people.
These are the first elections after the country joined the European Union in 2007 and the sixth since the fall of Communism in 1989.
Romania is a parliamentary republic with a bicameral parliament. The lower house Chamber of Deputies (Camera Deputatilor) has 325 seats and the upper chamber Senate (Senat) has 137 seats. Some 2,065 candidates are running for the Chamber of Deputies and another 895 for the Senate.
A party must win at least 5% of the total vote to enter parliament.
Three parties lead in the latest opinion polls but none of them is expected to win enough votes to form a government on its own.
Opposition centre-right Democratic-Liberal Party, PD-L, backed informally by President Traian Basescu, and the largest opposition group in parliament, the Social Democratic Party, PSD, led by former foreign minister Mircea Geoana, run neck-to-neck in the polls with more than 30% support each.