Soros told The Associated Press that right-wing parties in several countries such as his native Hungary are using hard economic times to stir up fears of ethnic groups such as Roma and reap gains in elections.
He cited the recent strong showing of Italy's Northern League, which paid "special attention to Roma."
"There is no question that the crisis that hits people unexpectedly, they don't know what's hitting them, it gets them angry and they want to take it out on someone. And the Roma are obvious targets," he said.
Soros is a longtime champion of the rights of Europe's largest ethnic minority.
He spoke on the sidelines of an EU meeting on how to end the plight of the continent's estimated 12 million Roma, who are present in all 27 EU countries but mainly eastern Europe and the Balkans. They suffer from widespread poverty and discrimination.
The two-day meeting is being held in Cordoba, a city in Spain's southern Andalusian region that is home to about half of Spain's 600,000 Gypsies.
The nomadic ethnic group tends to place a high value on the extended family, and its members sometimes lack the official identification, or permanent residency, needed to get good jobs. But Roma usually adopt the dominant languages and religions of their country of residence.
EU Justice Commissioner Viviane Reding said Roma, who trace their roots back to India hundreds of years ago, are now a part of Europe's social and cultural fabric and have contributed much to it.
"Just think about flamenco here in Spain, about music and art in Spanish society," she said in an opening speech.
Reding said living standards for Roma in Europe have deteriorated in recent years.
"Too many Roma children are still on the streets instead of being in school. Too many Roma are still denied a fair chance in the labor market and too many Roma women are still victims of violence and discrimination," Reding said.
Soros said the EU has been the driving force for helping to integrate Roma into mainstream society, spending 400 million euros on this in recent years. But he said the bloc needs a more comprehensive strategy for this funding.
"There is progress, but is not at all up to the size of the problem," Soros said.