According to Andriasang, 620,000 copies were shipped to the US, 470,000 to Europe and 370,000 to Japan, where it was only released on the PS3.
The figures are in stark contrast to the launch of its predecessor, which was originally due to be released only in Japan before hitting Europe more than a year later.
Dark Souls is the spiritual successor to role-playing adventure Demon's Souls, adopting an open-world format and a harder difficulty setting.
Dark Souls was released last month on Xbox 360 and PlayStation 3.
> Read Digital Spy's Dark Souls review
Watch the Dark Souls trailer below: