It is important to know when and where cavitation occurs in bearings because cavitation has an effect on both the power loss and stability of the bearing. A bearing without cavitation can very well be unstable (vibrating) for the same working conditions where a cavitating bearing is stable. A high-speed camera was used to investigate cavitation in dynamically loaded journal bearings. The length-diameter ratio of the bearing, the speeds of the shaft and bearing, the surface material of the shaft, and the static and dynamic eccentricity of the bearing were varied. The results reveal not only the appearance of gas cavitation, but also the development of previously unsuspected vapor cavitation. Analysis is given to support the experimental findings for both gas and vapor cavitation.