As a first work in the cannabinoid field we carried out a modeling study of CBRs, using the X-ray structure of bovine Rodopsine (pdb code: 1f88) as structural template. Docking studies with the most representative cannabinoids, described as partial agonists or antagonists / inverse agonists, were performed. The results confirmed the existence of two binding sites on both receptors. While in the CB1R was observed a clear overlap of both sites, in CB2R, the sites are clearly distinct. In both sites, receptor-ligand interactions are governed by a combination of hydrogen bonds and aromatic interactions.