Officials said election results will be available in about a month.
The parliamentary elections were the first since 1969 and capped an international political rebuilding plan aimed at returning democracy to Afghanistan after the ouster of the tyrannical Taliban regime in 2001.
"It is not the end of the international commitment," said U.S. Ambassador to Afghanistan Ronald Neumann. "I see the international community very strongly remaining in Afghanistan."
Experts said overall turnout on Sunday appeared to be 50 percent of the country's 12.4 million voters, lower than the estimated 70 percent turnout during the presidential election in October.
"We are making history," Afghan President Hamid Karzai told reporters just before casting his own votes. "It's the day of self-determination for the Afghan people. After 30 years of wars, interventions, occupations and misery, today Afghanistan is moving forward, making an economy, making political institutions."
Taliban militants had promised widespread violence on election day but reportedly followed through with only a few scattered attacks.
The Washington Post reported that a dozen people were killed in various attacks across the country. The dead included Afghan civilians, two Afghan police officers, three Taliban fighters and one French solider.
Afghanistan's 6,000 polling places were guarded by a force of 130,000, including Afghan police, U.S. and coalition forces, and NATO troops. Some 20 polling places were attacked with rockets or small arms fire.
A spate of violent attacks leading up to election day left six candidates and four election workers dead.
International observers said the violence along with other forms of intimidation and voting irregularities plagued some local areas but did not have an overall effect on the election.
"We did see some procedural irregularities but nothing that I consider systemic and which would have influenced the overall conduct of the election," Peter Erben, an officer with a United Nations-backed monitoring group, told the New York Times. "This was a peaceful and good election."
Reports from Afghanistan said that many of the candidates in Sunday's contests were tribal leaders, members of militias, or former warlords.
"If a warlord is voted in, I believe it sort of legitimizes that man," Qayoom Karzai, the president's brother and a candidate for Parliament, told the New York Times. "Hopefully, he will act as a clean man."