It took GTA IV's predecessor, 2004's GTA: San Andreas, three years to pass the 20 million mark. Across Xbox 360 and PS3, GTA IV blew past the halfway mark to that milestone in just nine months.
In GTA IV's first week of release in late April 2008, the game generated over $500 million in revenues.
The game also drove sales during Take-Two's November-January quarter, along with Carnival Games, NBA 2K9 and Midnight Club: Los Angeles.
The Carnival Games series, which includes Carnival Games for Wii and DS, and Carnival Games MiniGolf on Wii have sold a combined 4 million units worldwide, Take-Two added.
In the current fiscal quarter, Take-Two released the Xbox 360 exclusive downloadable content, The Lost and Damned, which Wedbush Morgan analyst Michael Pachter estimated to sell 2 million copies by year-end at $20 each.