Pre-election opinion polls predicted that the governing PCRM would win more than 36.2 per cent of the vote, ahead of the opposition Liberal Democrats, the Liberal Party and Our Moldova.
The PCRM had campaigned on pledges to stabilise the country in the face of the global financial crisis, as well as to maintain friendly ties with Russia.
Vlad Filat, the leader of the Liberal Democrats, said on Sunday that he hoped to unseat the communists for "Moldova to become a democratic and free state where human rights and freedoms are respected".
The new parliament is to choose a new president between April 8 and June 8 after Voronin's second term ends.
Voronin has been in power since 2001 when the Communist party was elected in a landslide victory on a pro-Russian ticket during parliamentary elections.
Moldova is one of Europe's poorest countries, with an average monthly salary of $350. Last year Moldovans abroad sent home $1.6bn - roughly the same amount as the state budget.
There has been some economic growth during the communists' eight years in power, but international groups have criticised Moldova's slow progress towards full democracy, and a lack of media freedom.
A Romanian-speaking province that imperial Russia and the Ottoman empire fought over for centuries, modern-day Moldova was annexed by the Soviet Union at the end of World War II.
The country has maintained strong ties with Moscow since the collapse of the Soviet era.