Microfluidics, the study of fluid flow through structures with micrometer scale dimensions, is an increasingly important discipline within a number of commercial and industrial applications. One focus of active microfluidic research at the Stanford University Microscale Heat Transfer Laboratories (MHTL) is mass and heat transport in two-phase flows, which has applications in the cooling of integrated circuits and the management of water created in PEM fuel cells. At its core, two-phase microfluidics is the study of interactions between moving liquids and/or gases and/or solids (though not necessarily stationary) structures. Advanced confocal microscopy, with its ability to visualize and measure both flow and structure on a single instrumental platform, will certainly play a key role in the continuing development of microfluidic devices.