Nissan made a net profit of 126bn yen between April and September, while it was 212bn yen a year earlier.
There was an overall 4.7% rise in sales, but in the US it fell 3.4%.
Nissan, looking ahead, has also warned that its profits for the financial year by the end of March can drop more than two thirds.
The company is expecting a net annual profit of 160bn yen, while it was 484bn yen a year back that is well short of the company’s 340bn yen previous forecast.
Nissan chief executive Carlos Ghosn said: “There is a deep effect of the global financial and economic crisis on almost every area of car industry and declining consumer confidence is indeed one of the most damaging factors.”
“We are taking all necessary measure to protect the company and preserve our ability to bounce back in the improved conditions,” he added.
Nissan has also said that it would stop production of two of its models at Sunderland plant in the North-East of England, as the demand is falling with every passing day and mainly due to economic downturn.