Several Asian stock markets, including Japan's Nikkei index, have fallen more than 3% in early trading as investors' worries about the US economy continued.
Prices on the Tokyo Stock Exchange fell 3.2% on Monday, taking the Nikkei to its lowest level since late September.
In Hong Kong, share prices fell 3.8% in the opening minutes of trade, while the Taiwan Stock Exchange lost 2.82%.
There are also fears of sharp falls on European stock markets on Monday after Friday's hefty losses on Wall Street.
The Dow Jones, the main US share index, fell 367 points on Friday, the 20th anniversary of the Black Monday stock market crash.
Most of the falls came after European markets closed, so they will have their first chance to react on Monday.
The falls were set off by concerns that the full effects of the US housing slowdown have not yet been seen.
It started when the building equipment firm Caterpillar cut its profit forecast, blaming the state of the economy
"It's pretty ugly," said Bill Strazzullo, chief market strategist at Bell Curve Trading.
"A company like Caterpillar should be a poster child for global growth and benefits of the weak dollar," he said.
"It makes you question: Is global growth really that strong? Has the earnings kick from the weak dollar played itself out?"
On Black Monday, the Dow Jones fell 23%, which nowadays would mean a drop of more than 3,000 points.
"I think we're responding emotionally to the 20th anniversary of the October 1987 stock market crash," said Andy Brooks, head of trading at T Rowe Price.
"I'd like to laugh except it hurts," he added. ( BBC )