When God of War 3 was complete, Sony's Santa Monica Studios said that Kratos' story is pretty much done and over with...but that's just Kratos and not the God of War franchise. Nothing's been heard since about God of War, but today, something very interesting came up.
PSM3, an unofficial Playstation Magazine, has confirmed from an anonymous source of theirs, who actually does work at Santa Monica, confirmed that a new installment will be arriving in September 2012. It's not official at all, nor is it known if it's exactly going to be "God of War 4," or some sort of spin off, but it makes sense that there would be more, but without Kratos. Only time will tell or if proven false...