Migration of microglial cells towards damaged tissue plays a key role in central nervous system regeneration under pathological conditions. Using time lapse video microscopy we show that lysophosphatidic acid (LPA) enhances chemokinetic migration of murine microglial cells. In the presence of 1 µm LPA, the mean migration rate of microglial cells was increased 3.8-fold. In patch-clamp studies we demonstrate that LPA induces activation of a Ca2+-activated K+ current. Microglial Ca2+-activated K+ currents were abolished by either 50 nm charybdotoxin or 10 µm clotrimazole. In contrast, 5 µm paxilline did not have any significant effects on Ca2+-activated K+ currents. The LPA-stimulated migration of microglial cells was inhibited by blockers of IKCa1 Ca2+-activated K+ channels. The mean migration rate of LPA-stimulated cells was decreased by 61% in the presence of 50 nm charybdotoxin or by 51% during exposure to 10 µm clotrimazole. Microglial migration was not inhibited by 5 µm paxilline. It is concluded that IKCa1 Ca2+-activated K+ channels are required for LPA-stimulated migration of microglial cells.