Sony has said it sold 500,000 PSP handheld consoles in the first two days on sale in the United States, half of the allocation to the country.
European gamers have to wait to play PSP
Some analysts said the device was not selling as fast as some large chains had expected, reported Reuters.
Sony said the PSP generated a total of $150m (£80m) in first-week sales at North American retailers, but did not give second-week figures.
The PSP is a games console which can also play movies and music.
The console came out late last year in Japan and has sold more than one million units in the country to date.
Sony postponed the European launch of the PSP indefinitely so that it could ensure an adequate supply for the US launch, which it promised would be about one million units.
Analysts expect sales of handheld games to drive growth of the video game industry in 2005.
Rival handheld console, Nintendo's DS, has already launched in Europe, as well as the US and Japan.
Nintendo has said it expected to sell five million DS units world-wide by the end of March 2005.