The prime minister called the vote three years early amid mass protests and accusations of corruption.
The opposition has boycotted the election and is vowing to continue protests until Mr. Thaksin resigns.
Voter turnout was peaceful and orderly as millions of Thais passed judgment on the government of Prime Minister Thaksin Shinawatra - which they re-elected by a landslide barely more than one year ago.
Some voters, like automobile parts dealer Pichet Prayoonthong, says the Thaksin government was elected democratically and the protests should stop because they are beginning to hurt business.
Mr. Pichet said, "I don't think our prime minister to quit. This is not the way to solve the problem. Everyone should talk to each other."
Others, like shop owner Siriphatsorn, says the Thaksin government is corrupt and authoritarian. She wants a change.
Mr. Siriphatsorn said, "We want to chase away some bad people. We don't want bad people to control our country anymore. We don't want legal corruption."
Many Thais have voiced anger over reports of corruption and abuse of office by the Thaksin government.
Weekly street protests in Bangkok began after January when the Thaksin family sold nearly two billion dollars worth of stock, tax-free, in the company the prime minister founded.
Retired grocer Chur says what is needed is a return of morality to government.
He says the Thai constitution is a good document, but dishonest people have altered it for their own benefit, which is not fair.
Some voters, like clothing maker Sunthorn Sinwattanacharoen, say the constitution must be revised.
He says the constitution as it is could solve some of the problems, but we have no other choice now, we must amend it to prevent further abuses.
Yet others, like his wife, Wimon, voiced fatigue over the prolonged crisis and the uncertainty it is causing.
She says we just want the crisis to end soon. We love Thailand. We love the king.
Mr. Thaksin, after voting Sunday morning, made only a brief comment to reporters.
Mr. Thaksin said, "This is democracy."
The prime minister says that after the election he would consider all his critics' complaints.
The opposition, which is boycotting the vote, says the protests will continue until Mr. Thaksin resigns.
The election may not resolve the political standoff. Because of the boycott, some seats in parliament may not be filled, which could delay the opening of parliament and the election of the new government for some time.
Authorities worry that a prolonged delay could aggravate tensions between the two sides.