By Agence France-Presse
The parade, estimated to be some 30,000 strong, made its way through the South Korean capital with participants dancing on open truck beds decorated with slogans and waving the rainbow flag of gay rights.
In recent years extreme conservatives and evangelist Christians have held rival rallies in attempts to block the progress of the annual march and put on their own performances to try and disrupt the festivities.
Fences were set up around the Seoul Square outside the City Hall Saturday and hundreds of police were deployed to keep the revellers and protesters apart.
Hundreds of Christians, waving flags with Christian crosses printed on them and thumping on drums, chanted anti-gay slogans and sang patriotic and evangelical songs.
Public tolerance towards sexual minorities in South Korea's tradition-bound society has been growing in step with the country's democratic development.
Homosexuality is not illegal but fears of discrimination and social isolation still prevent many people from coming out.
"I think the public attitude toward homosexuality has become much more receptive over the past few years", said a parade participant who identified himself as Psygay as he handed out leaflets promoting the country's gay rights movement.
"However, hate groups' animosity toward LGBT people has intensified all the more", he told AFP.
When he came out three years earlier, his mother and the only brother were shocked and saddened.
"After a while, my mother said she understood me as I am her son anyhow. But my brother still urges me to change", he said.
"My father? Oh, he still doesn't know", said Psygay.