Homodimerisation is producing a protein?protein complex composed of two identical molecules. Dimerisation is a phenomenon often occurring in the regulation of biochemical systems like signal transduction pathways. We investigated whether the existence of a homodimer-activated receptor and the activation of homodimer transducers correspond to a more general pattern in cell signalling. We developed a workflow to merge data from the Gene Ontology and the BIND database to produce a list of interactions between homodimer receptors and homodimer proteins. Finally, we found a prevalence of homodimer-homodimer interactions in signalling systems in human cells.