The four-day congress will draw attention to the plight of gypsies in Kosovo, who have been subjected to violence by ethnic Albanians.
It is the first session of the International Romany Union (IRU) for 10 years, and the fifth ever held.
The four-day congress will draw attention to the plight of gypsies in Kosovo, who have been subjected to violence by ethnic Albanians.
A recent report by the European security organisation, the Organisation for Security and Co-operation or OSCE, said that gypsies faced what amounted to "pogroms" in some European countries.
Communism's safety net
The OSCE's High Commissioner on National Minorities, Max van der Stoel, highlighted problems experienced by the gypsy community - or Roma - in gaining access to jobs, housing, education and health care.
The report said that the collapse of the universal social safety net provided by communism had left many gypsies almost total outcasts.
Correspondents say they suffer from widespread discrimination and abuse as well as economic difficulties.
Gypsy leaders are reported to have chosen Prague for the congress for symbolic reasons. The Czech Republic has been repeatedly criticised over its treatment of its Roma minority, notably by the European Union which it is trying to join.
Self-help
In Kosovo, where the United Nations estimates there are 30,000 gypsies, they have increasingly been attacked over the past year by ethnic Albanians who see them as allies of the Serbs.
And an IRU spokesman said that the congress would discuss payments to the Roma from a $5bn fund recently set up by the German government to compensate those forced into slave labour by the Nazis.
Analysts say that previous efforts to strengthen the gypsies' position have failed because of a lack of organised leadership.
The International Roma Union tries to redress that problem by speaking on the gypsies' behalf, but many of the delegates themselves are unelected.
Those attending the congress include prominent gypsy activists, singers and actors as well as the self-styled King of the Romanies, Florian Cioba, who is from Romania.
The BBC's Ray Furlong says that another issue at the conference will be the standardisation of the Roma language, which is related to the ancient Sanskrit tongue of India, from where the gypsies migrated 1,000 years ago.
Now, most live in eastern Europe, mainly Romania, the Czech Republic, Slovakia, Poland, Bulgaria, Hungary and Turkey.