© Springer Science+Business Media, LLC, part of Springer Nature 2018. The G protein-coupled receptor heterocomplex network database (GPCR-hetnet) is a database designed to store information on GPCR heteroreceptor complexes and their allosteric receptor–receptor interactions. It is an expert-authored and peer-reviewed, curated collection of well-documented GPCR–GPCR interactions that span the gamut from classical GPCR–GPCR interactions to more complex receptor–receptor interactions (GPCR-Receptor Tyrosine Kinase and GPCR-ionotropic receptor/ligand gated ion channel). Although GPCR-hetnet contains interactions among GPCR from several different species, the curators have initially focused on receptor–receptor interactions in humans. Currently (August 2017) GPCR-hetnet contains information on 250 receptors (192 GPCR, 52 RTK, and 6 ionotropic receptors) and >1023 interactions. The GPCR-hetnet provides four searchable datasets: the hetnet, the non-hetnet, the rtknet, and the ionnet. Other supporting datasets include information about receptors that are present in GPCR-hetnet such as literature citations. This chapter describes in a basic protocol how to use, navigate, and browse through the GPCR-hetnet database to identify the clusters in which a receptor protomer of interest is involved, while further applicability are also described and introduced.