Nintendo has made a loss of ¥2.01 billion ($24.5m / £15.5m) for the first six months to September 30, 2010, compared to a profit of ¥69 billion ($848.3m / £537.4m) for the same period last year.
Sales for the period were down to ¥363.1 billion ($4.4bn / £2.8bn), compared to ¥548 billion ($6.7bn / £4.2bn) in 2009. Operating profit for the period fell to ¥54.23 billion, down from ¥104.36 billion a year earlier.
Sales of the DS handheld were down to 6.69 million units for the six months, compared to 11.7 million last year. Software for the machine sold 54.8 million units, down from 71.1 million.
Wii hardware sales also fell, from 5.75 million units in the first six months of 2009 to 4.9 million units. Software for the home console sold 65.2 million units, down from 76.2 million units.
Pokemon Black Version and Pokemon White Version for the DS have sold 4.07 million units in Japan, said Nintendo, while Super Mario Galaxy 2 has sold 5.1 million units worldwide.
As well as low sales, Nintendo also blamed the appreciation of the yen for the six month results.