Bisphosphonates are pharmacological agents which are currently used both in osteoporosis than in other pathological conditions characterised by an increased bone resorption, such as Paget's disease of bone, malign hypocalcaemia during myeloma, osteolytic bone metastasis and fibrous dysplasia of bone. The most important biological effect of bisphosphonates is the reduction of bone remodelling through the inhibition of osteoclastic activity, but there are many clinical and experimental evidences of extra-skeletal biological effects of bisphosphonates. It has been shown that bisphosphonates exert their effects not only on bone tissue cells, but also on those of the immune system with an “immuno-modulating” effect, influencing the production of pro- and anti-inflammatory cytokines and changing the molecular expression involved in the immune processes and anti-inflammatory response. Although the available data are conflicting, there are several reports concerning the beneficial effects of bisphosphonates in controlling the progression of chronic joint inflammatory diseases, suggesting a wider use for these therapeutic agents in clinical practice.