I’ve worked with multiple Project managers. I agree with Puneet that there are both positives and negatives to having multiple project managers. It can get confusing with where to draw the line on different responsibilities and deliverables but as Sahitya mentions it can also be valuable to have multiple managers provide a certain expertise that the other may lack. I personally think Projects should be structured as Scott described in which there is only one official Project Manager, but there can be sub-categories for management based on the particular department/roles. I think like akshayakirithy, having one official project manager is ideal so that there is a man point person who oversees the project so that there is focused plan.