The skeleton is maintained throughout life via the finely tuned actions of osteoblasts and osteoclasts, with disruption in this balance eventually leading to bone disease. The exact mechanisms balancing these actions are not fully known, although several regulatory systems are known to be involved. The involvement of purinergic signalling in bone has come to light over the past 20 years or so. This review will highlight the current knowledge of purinergic signalling in osteoblasts - covering expression of P2 receptors, mechanisms of ATP release and degradation, P2 receptor mediated signalling and finally the functional consequences of P2 receptor signalling in bone.