The Election Commission of Thailand (ECT) ordered the revotes due to suspicion of poll fraud and vote-buying.
The ECT called for revotes to make sure those elected committed no fraud or bought no votes.
6 election, army and police officers have been deployed to guard the revote counting.
The revote is unlikely to change the election outcome in which telecom billionaire Thaksin Shinawatra's Thai Rak Thai Party won the most seats of the 500-member House of Representatives, far ahead of its closest rival Democrat Party of now outgoing Prime Minister Chuan Leekpai.