The current status of ligand gated ion channel P2X and G protein-coupled P2Y receptor subtypes is described. This is followed by a summary of what is known of the distribution and roles of these receptor subtypes. Potential therapeutic targets of purinoceptors are considered, including those involved in cardiovascular, nervous, respiratory, urinogenital, gastrointestinal, musculo-skeletal and special sensory diseases, as well as inflammation, cancer and diabetes. Lastly, there are some speculations about future developments in the purinergic signalling field.