Japan's exports plunged 45.7% in January compared with a year ago to hit the lowest figure in 10 years, official figures have shown.
Imports exceeded exports by 952.6bn yen ($9.9bn; £6.8bn). It is the largest gap since records began in 1980.
Demand for Japanese cars in particular dropped by 69%.
Trade in electronics and other goods has also slumped as global economies and consumer spending contract, pushing Japan deeper into recession.
"Japan is particularly vulnerable to this downturn because trade is so central to the economy," World Trade Organization head Pascal Lamy told reporters on a visit to Tokyo.
Japanese exports to the US, where the global downturn began, fell nearly 53% in January, while shipments to the European Union shrank by 47%, Japan's finance ministry said.
JAPAN CARMAKERS' EXPORTS
Toyota - down 57.1% in January from a year earlier
Honda - down 46.3%
Nissan - down 62.1%
Mitsubishi - down 77.4%
Mazda - down 72.1%
Suzuki - down 56.1%
Source: Company results
"Exports to Asia, particularly to China, are tumbling at about the same pace as shipments to the United States, signalling that even China's economy may be shrinking," said Takeshi Minami, chief economist at Norinchukin Research Institute.
Exports to Asia dropped 47%, while those to China fell 45%.
The government said last week that Japan's economy was in its most serious crisis since World War II, after it contracted at an annualised rate of 12.7% in the last quarter of 2008.
This was its worst performance in almost 35 years, officials said.
Among those hit hard by the global downturn are export-oriented Japanese electronic makers.
As well as carmakers, they have had to cut output and eliminate jobs amid a sharp drop in global demand.
Pioneer has announced 10,000 job cuts and Sony is trimming its global workforce by 8,000 positions.
Meanwhile, Japan's government is pushing bills through parliament to implement a stimulus plan, including a cash handout of at least $130 for each Japanese taxpayer, the BBC's Roland Buerk reports from Tokyo.
But any bold moves may be difficult to push through because of the unpopularity of Prime Minister Taro Aso, our correspondent says.
US President Barack Obama and Mr Aso have agreed to work together to stimulate economic demand and fight protectionism as the latter visits the US.
The US and Japanese economies are respectively the world's largest and second-largest.