Bethesda man Pete Hines has said the company "clearly intended" to make more than one Fallout game when it bought the rights to the series.
"The whole reason we went out and acquired the licence and that we now own Fallout is that we clearly intended to make more than one," Hines told TVG. "This is not something we're going to do once and then go away and never do it again.
"When that will be or how long that will be god only knows, but we acquired it specifically because we wanted to own it and develop it and work on it like we do with The Elder Scrolls," he added.
However, Hines publicly talked of sequels after licensing Fallout 3 (and Fallout 4, Fallout 5) back in 2004.
The company acquired full rights to the series from Interplay in 2007.
Fallout 3 is in development for PC, Xbox 360, and PS3. But you will need a PC or an Xbox 360 in order to access downloadable content for the game, as Bethesda announced during E3.
Head over to our E3 hands-on impressions of Fallout 3 to find out more.