Repetitive action potentials with a maximal frequency of 5 Hz were induced by injection of depolarising currents in osteoblast like MG-63 cells or primary osteoblast cells. A detailed electrophysiological analysis of the expressed voltage dependent ion channels showed that depolarisation above a threshold of about -30 mV induced an inward current which was related to opening of tetrodotoxin (TTX) sensitive Na_v channels. The depolarisation also activated an outward current related to opening of delayed and tetraethylammonium (TEA) sensitive K_v channels. Strong rectifiers K_ir channels were opened by hyperpolarising voltages below -60 mV. Accordingly, RT-PCR experiments revealed the expression of TTX sensitive Na_v1.3, 1.4, 1.6, and 1.7 channels, slow activated and TEA sensitive K_v2.1 channel, as well as the strong rectifier K_ir2.1, 2.3, and 2.4 channels in osteoblasts. This report, which represents a first functional characterisation of ion channels in the osteoblasts shows that voltage dependent ion channels could be involved in osteogenesis.