Japan's trade deficit widened to $17.4 billion in January, the worst monthly figure on record for the world's third biggest economy.
The data released Wednesday by Japan's finance ministry showed an encouraging rebound in exports, which rose 6.4 percent last month, compared to a year earlier.
But imports increased more dramatically at 7.3 percent, as resource-starved Japan continued to increase its reliance on oil and gas from other countries.
Japan's fuel imports have risen since its 2011 earthquake and tsunami disaster, which forced most of its nuclear power plants offline.
Making matters worse, the price of imported fuel has risen in the past few months, as Japan's currency weakens.
Investors disregarded the bad economic news Wednesday, however, as Tokyo stocks closed 0.84 percent higher.