To my bitter disappointment, the Content Query Web Part in SharePoint 2010 wont group results by Content Type as it used to in WSS 3.0. I am not sure why that is but we ended up binding an SPGridView to an SPDataSource and setting the SPGridView.AllowGrouping to true and also specifying the a GroupField=”ContentType”. I hope this changes in the upcoming Service Pack even though I have no personal interest in the CQWP Smile