Nintendo's Wii console outsold Sony's PlayStation 3 in Japan last month by six to one, says research.
Nintendo Wii has proved enormously popular
Nintendo sold 270,974 Wii consoles last month while Sony sold 41,628 PS3s, according to Enterbrain, a Japanese publisher that tracks console sales.
Nintendo has sold about 2.76m Wii consoles in Japan since the launch last December, while Sony has sold 970,270 PS3s since it debuted last November.
About 17,616 Xbox 360 consoles were sold in June.
Last week, Phil Harrison, PlayStation's head of worldwide studios, told US Game Informer magazine that pundits should not judge the success of the console based on the launch software line-up.
He said: "You only have to go back to the games that launched PlayStation 1 and Playstation 2.
"If you took those few dozen titles and analysed them, you would never have imagined that either of those formats would have on to sell over 100m units each."
Globally, Sony has struggled so far to replicate the success it had with the first two PlayStation consoles.
The machine has also suffered from a lack of "killer" exclusive titles which showcase the power of the machine.
PlayStation fans are still awaiting some of the biggest franchises on the machine to emerge, such as Metal Gear Solid, Killzone 2 and Gran Turismo.