Multiple myeloma is characterised by the clonal expansion of malignant plasma cells. Recently, we reported that a new cytokine, hepatocyte growth factor (HGF), and its receptor c-met are related to this disease. Here we review the observations that associate HGF with myeloma. Malignant plasma cells produce HGF and express the receptor c-met. Many patients have elevated HGF levels, which is unfavourable both in terms of survival and response to treatment. Possible biological roles of HGF in this disease are discussed, with special focus on bone homeostasis and its binding to heparan sulphate proteoglycans.