It is possible to combine agile and CMMI approaches together, as a quick Internet search will reveal. That same Internet search will also show that a small percentage of organizations are in fact doing so, regardless of the protestations of many agile purists. There appears to be a fair bit of evidence showing that applying agile within CMMI environments appears to improve the situation. However, it is our observation that applying CMMI to agile teams tends to decrease their effectiveness in practice.
disciplinedagiledelivery.com (via LinkedIn) by Scott W. Ambler