The event, which brings together around 400 delegates and heralds from 26 countries, including South Africa, Russia, Canada, Spain and Norway, was opened by its patron, HRH Princess Anne, the Princess Royal at a special ceremony in St Andrews University's Younger Hall.
The ceremony opened with a song of welcome sung in Gaelic by Wilma Kennedy, Broughty Ferry.
Greeting the delegates in English and French, Princess Anne thanked those in attendance for inviting her to become their patron and to be part of what she said was an "international forum".
"Heraldry and genealogy have always been a very important part of our upbringing," she said.
"I grew up surrounded by heraldry, but I also knew that I know far too little about it."
Describing genealogy as "history with a future," Princess Anne said the subject was more important than ever before and carried the link between our past, our present and our future.
The university and the burgh of St Andrews were also presented with specially created heraldic processional banners or 'gonfannons,' which were blessed by the Archbishop of St Andrews and Edinburgh, Cardinal Keith O'Brien.
Also in attendance were Liberal Democrat leader and university chancellor, Sir Menzies Campbell, Donald McGregor, chair of St Andrews Community Council and George Reid MSP, presiding officer of the Scottish Parliament.
Following the ceremony, hundreds of spectators turned out to watch a procession led by president of the congress Dr Luc Duerloo as the delegates set off, decked out in richly decorated robes, along North Street to the sound of pipers.
The public also took part in a free family history and heraldry fair on Wednesday and an exhibition "Who Do You Think You Are?" is being held at St Andrews Museum until September 3.

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