The discovery that G protein-coupled receptors (GPCRs) do not necessarily function alone has dramatically changed the way that pharmacologists view the world of cell signalling. The GPCR family is currently the main target for drug discovery, and GPCR dimerization broadens our outlook because not only do GPCRs dimerize with the same GPCR (homodimerization) but they can also dimerize with GPRCs from other receptor families (heterodimerization). These processes greatly enhance our options for manipulating receptor activity and therefore offer great targets for drug discovery.