The aim of the study was to evaluate serum levels of FLT3-ligand (FLT3-L), a soluble molecule in bone marrow (BM), participating actively in hematopoiesis, in relation with angiogenic factors in multiple myeloma (MM) patients. We measured, in 70 patients with active MM and in 38 of them who responded to conventional therapy, serum levels of FLT3-L, along with known angiogenic factors, such as VEGF, endoglin, TNF-alpha and HGF (with ELISA) and BM microvascular density (MVD), estimating the immunohistochemical expression of CD31. All pre-treatment values were higher in active MM patients compared to controls (p