Whereas most membrane receptors are oligomeric entities, G‐protein‐coupled receptors have long been thought to function as monomers. Within the last 15 years, accumulating data have indicated that G‐protein‐coupled receptors can form dimers or even higher ordered oligomers, but the general functional significance of this phenomena is not yet clear. Among the large G‐protein‐coupled receptor family, class C receptors represent a well‐recognized example of constitutive dimers, both subunits being linked, in most cases, by a disulfide bridge. In this review article, we show that class C G‐protein‐coupled receptors are multidomain proteins and highlight the importance of their dimerization for activation. We illustrate several consequences of this in terms of specific functional properties and drug development.