Vasculotropin/vascular endothelial growth factor (VAS/VEGF) is an angiogenic growth factor whose biological activity seems to be restricted in vitro to vascular endothelial cells. We describe here that fetal bovine osteoblasts (OB) bind VAS/VEGF but do not proliferate upon its addition. However VAS/VEGF induces migration, PTH-dependent cAMP accumulation and alkaline phosphatase increase when added to OB. The maximal effects reach levels comparable to that obtained with bone morphogenetic protein 2 (BMP-2), although the VAS/VEGF concentrations required are at least 100 fold lower. Our results suggest that VAS/VEGF could be an important regulator of osteoblastic differentiation.