The monocyte migration induced by the media, as the source of chemotactic factor,conditioned by cultured rabbit aortic smooth muscle cells, was assayed by micropore filter method using modified Boyden chamber;the effects of extracellular Ca²⁺ at different concentrations and verapamil on the monocyte migration were observed as well.Furthermore, the influences of above-mentioned conditioned media and verapamil on monocyte cytosolic free Ca²⁺ concentration, [Ca²⁺]i, which was determined by using Fura-2 measurement, were observed. The results showed that the conditioned media were significantly chemotactic for monocytes and its chemotactic activity was inhibited by verapamil; the media also significantly increased [Ca²⁺]i that were inhibited by verapamil as well.Extracellular Ca²⁺ had also some influences on monocyte migration. The results suggest that monocyte migration are dependent on both cytosolic free Ca²⁺ and extracellular Ca²⁺.