In Thailand's resort of Pattaya, the contestants are part of a kissing marathon in an attempt to beat the current 32-hour record which was set in Germany last year.
The couples have each been given a space of one square metre and they must lock lips at all times, and cannot sit, sleep or leave the venue, or they will be disqualified.
One woman has fainted after 34 minutes of kissing. Others have given up after a few hours.
The couple that last longest will receive a diamond ring worth £1,000 and a £2,000 cash prize.
Felix Werth, 32, one of the contestants said: 'I just participate for fun and I'm looking forward to kissing for a long time.'
The contest began on Sunday at 11pm GMT and will continue throughout Valentine's Day.
