The Wii was launched in 2006
Nintendo's profit fell by 52% in the six months from April, as waning sales of its Wii console forced the firm to cut full-year earnings forecasts.
Net income dropped to 69.5bn yen ($762m; £460m) in the six months to September, from 144.8bn yen a year earlier, the company said.
The Kyoto-based firm has now reduced its full-year forecast to 230bn yen in the year to March 2010.
The Wii lost the best-selling console slot in the US and Japan in September.
Nintendo cut Wii prices by 20% after rivals Sony reduced the cost of its PlayStation 3 by 25%.
Hitachi also released disappointing figures on Thursday.
The company said its net loss for the quarter ending in September grew to 50.5bn yen from the 17.3bn yen loss it made a year earlier.
In contrast, Sharp credited booming TV sales and cost cutting for profit more than doubling to 7.4bn yen in the second quarter from 3.1bn yen during the same period last year.