Asia's losses came despite strong U.S. job numbers that sparked a Wall Street rally on Friday.
Hong Kong's Hang Seng dropped 1.9 percent to 20,463.80 and China's Shanghai Composite was down 1.6 percent to 1,974.82. Most other regional markets also fell amid renewed worries that economic recovery in China, the world's No. 2 economy, is faltering.
IMF Director Christine Lagarde warned at a conference in France on Sunday that a slowdown in emerging economies could result in the fund lowering its 2013 forecast for world growth.
The Chinese central bank's clampdown on easy credit has fueled additional concern. Michala Marcussen of Societe Generale Group said in a commentary that credit data due out this week would likely show a slowdown in lending.
"This data will do little to change the picture of credit tightening in China, pointing to slower growth ahead," Marcussen said.
South Korea's Kospi dipped 1.1 percent to 1,813.13. Taiwan's TAIEX fell 1.1 percent to 7,913.22 and Indonesia's JSX was down 2.1 percent to 4,505.61.
Japan's Nikkei 225 was up 0.2 percent to 14,338.62 as the yen resumed its weakening trend, which is a perk for Japanese exporters.
World markets have been volatile in recent weeks as investors worried that an improving U.
But those worries were put aside Friday after the Labor Department reported that the U.S. added a stronger-than-expected 195,000 jobs last month, suggesting the economy is healthy enough to cope with a withdrawal of the Fed's stimulus.
The Dow Jones industrial average rose 147.29 points to 15,135.84. The S&P 500 rose 16.48 points to 1,631.89. The Nasdaq composite climbed 35.71 to 3,479.38.
Benchmark crude for August delivery was up 33 cents to $103.55 a barrel in electronic trading on the New York Mercantile Exchange. The contract gained $1.98 to $103.22 on Friday.
In currencies, the euro fell to $1.2816 from $1.2828 late Friday. The dollar rose to 101.25 yen from 101.21 yen.