G protein-coupled receptors (GPCR) play an important role in drug development. Although many classical signal transduction pathways have been elucidated, more and more cross-talk to other cascades, e.g. MAP-kinase have been reported. In order to identify the overall function of receptor stimulation in a specific cell type or under certain conditions proteome analysis has been shown to be a very successful and powerful approach. Here, we will summarize the current state of the art of proteome analysis applied to GPCR.