The United States has congratulated the people of Bhutan for holding elections to choose their first democratic government.
People queued for a long time to cast their votes.
The US state department said the vote marked "another positive step in Bhutan's transition to a democratic, constitutional monarchy."
Unofficial results show that the party of the former Prime Minister, Jigme Thinley, won a landslide victory.
The move to democratic rule was proposed by Bhutan's royal family.
A Japanese election observer, Takio Yamada, praised the way the vote had been conducted:
"I think this is a success, a great success and great achievement for the Bhutanese people.
"This is a great step forward to achieving real democracy in this country."
Election commissioner Kunzang Wangdi said the Bhutan Harmony Party had won 44 of the 47 seats in the lower house.
A candidate for the winning party, Ugyen Tshering, said the result was positive for everyone:
"We have not planned to have any grand celebrations.
"I think this victory is not about celebrating a victory over the other party, but this victory is a victory for the whole country."
The vote for the National Assembly completes the country's peaceful transition from an absolute monarchy to a constitutional monarchy.
An election for the upper house of parliament, the 25-seat National Council, was held in December.
The tiny Buddhist kingdom has been preparing for democracy since former monarch Jigme Singye Wangchuck decided to hand power to an elected government.
The country is now headed by his 28-year-old son, King Jigme Khesar Namgyal Wangchuck, who will remain as head of state and is likely to retain some influence.
The BBC's Chris Morris in Thimphu says many Bhutanese are still ambivalent about democracy, anxious that change should not come too quickly.