By using the whole cell voltage-clamp technique, we studied changes in plasma membrane permeability at different meiotic stages of bovine oocytes. Follicular oocytes were matured in vitro and activated by Ca²⁺ ionophore. Oocytes at germinal vesicle (GV), germinal vesicle breakdown (GVBD), metaphase I (MI), metaphase II (MII), and meiosis exit were used for electrophysiological recording. By clamping the oocytes at 30 mV, we found that the L-type voltage-dependent Ca²⁺ channels were active at the GV stage and that their activity decreased after the GVBD stage. Furthermore, the resting potential decreased from the GV to the MI stage and increased again at MII. A significant decrease of the steady-state conductance occurred from the GV to the MI stage, followed by a sharp increase at the MII stage. With the addition of organic L-type Ca²⁺ channel blockers (nifedipine and verapamil), we inhibited the Ca²⁺ currents. However, only in the case of verapamil was there a decrease of in vitro maturation efficiency. Our results suggest that, in addition to the cumulus-oocyte junctions, the plasma membrane channels provide another mode of Ca²⁺ entry into bovine oocytes during meiosis.