In response to adenosine 5-diphosphate, purinergic receptors P2Y1R and P2Y12Rregulate platelet activation and thrombus formation, and thus serves as important antithrombotic drug targets.Here we report the crystal structures of human P2Y12R in complex with an antagonist AZD1283, with a full agonist 2-methylthio-adenosine-5-diphosphate (2MeSADP), and with the corresponding ATP derivative 2-methylthio-adenosine-5-triphosphate (2MeSATP).